Biology New Information

Question 1

Where is blood pumped into in the heart?

Answer 1

aorta, which branches into a series of arteries

Question 2

What do the arterie the branch into?

Answer 2

arterioles and then into microscopic capilaries

Question 3

What is exchanged across the capillary walls?

Answer 3

gases, nutrients and cellular waste products occurs via diffusion

Question 4

How is blood brought back to the heart?

Answer 4

The capillaries then converge into venules and eventually into veins, which carry deoxygenated blood back toward the heart

Question 5

Explain the heart sides (right and left)

Answer 5

Right side = deoxygenated blood into pulmonary circulation (toward the lungs)

Left side = oxygenated blood into systematic circulation (throughout the body)

Question 6

What are the two upper chamber and two lower chambers of the heart called

Answer 6

Upper chambers = atria (thin walled)

lower chambers = ventricles (muscular)

The left ventricle is more muscular than the right because it is responsible for generating the forse that propels the systemic circulation and because it pumps agains the higher resistance

Question 7

In patients with increased systemic resistance (artaries clogged), what happens to the heart?

Answer 7

the left ventricle can become hypertrophied (enlarged) which over time can lead to congestive heart failure and other cardiovascular diseases

Question 8

Explain the process of blood flow through the heart

Answer 8

1. Blood returning from the body first flows through the right atrium, then through the tricuspid valve into the right ventricle
2. finally through the pulmonary semilunar valve into the pulmonary arteries to continue to the lungs
3. Blood returning from the lungs flows through the pulmonary veins into the left atrium
4. then through the mitral valve into the left ventricle
5. Finally through the aortic semilunar valve into the systemic circulation

Question 9

What are the valves in the heart, location and purpose?

Answer 9

• Atrioventricular valves, located between the atria and ventricles on both sides of the heart, prevent backflow of blood into the atria
  
  • right side = tricuspid valve
    
    • because it has three cusps
  • left side = mitral valve
    
    • becaue it has two cusps
• Semilunar valves
  
  • have three cusps
  • located between the left ventricle and aorta and between right ventricle and pulmonary artery

Question 10

What is the “lub-dub” sound from?

Answer 10

made by the successive closing of the atrioventricular and semilunar valves

Question 11

What is the heart’s pumping cycle described as?

Answer 11

• two alternating phases: = heatbeat
  
  1. Systole
     
     • Period during which the ventricles contract, forcing blood out of the heart into the pulmonary and systemic circulation
     • Blood vessel contraction pressure
  2. Diastole
     
     • period of cardiac muscle relaxation during which the blood drains into all four chambers
     • pressure during cardiac relaxation
• Together they make blood pressure measurement

Question 12

How is cardiac output defined by?

Answer 12

The total volume of blood the left ventricle pumps out per minute

Cardiac output = heart rate (number of beats per minute) x stroke volume (volume of blood pumped out of the left ventricle per contraction

Question 13

Explain how the heart rate is controlled by the body

Answer 13

• Cardiac muscle contracts rhythmically without stimulation from the nervous system, producing impulses that spread through its internal conduction system
• Ordinary cardiac contraction originates in, and is regulated by the sinoatrial (SA) node (the pacemaker) a small mass of specialized tissue located in the walls of the right atrium
  
  • SA note spreads impulses through both atria, contracting simultaneously
• Impulses arrive at the atrioventricular (AV) node, which slowly conducts impulses to the rest of the heart, allowing enough time for atrial contraction and for the ventricles to fill with blood
• The impulses is then carried by the bundles of His (AV bundles), which branches into the right and left bundle branches
• Then through the Purkinje Fibers in the walls of both the ventricles, stimulating a strong contraction to rest of body

Question 14

What innervates the heart

Answer 14

• The autonomic nervous system modifies the rate of the heart contraction
• The parasympathetic nervous system innervates the heart via the vagus nerves and causes a decrease in heart rate
• The sympathetic nervous system innervates the heart via the cervical and upper thoracic ganglia and causes an increase in heart rate
  
  • Adrenal medulla exerts hormonal control via epinephrine (adrenaline) secretion, increasing heart rate

Question 15

Name and describe the three types of blood vessels

Answer 15

1. Arteries = thick walled, muscular, elastic vessels that transport oxygenated blood from heart,
   
   • except for the pulmonary arteries which transport deoxygenated blood
2. Veins = relatively thin walled, inelastic vessels that conduct deoxygenated blood to heart
   
   • except for the pulmonary vein which transports oxygenated blood
   • Most have valves, especially in legs, that prevent backflow
3. Capillaries = smallest diameter, red blood cells must often travel through them single file
   
   • Location of where nutrients readily diffuse

Question 16

Explain the lymph vessels

Answer 16

• secondary circulatory system distinct from the cardiovascular circulation
• vessels transport excess interstitial fluid, called lymph, to the cardiovascular system, thereby keeping fluid levels in the body consistant
• Smallest lymphatic vessels (lacteals) collect fats, in the form of chylomicrons, from the villi in the small intestine and deliver them into the bloodstream, bypassing the liver
• Lymph nodes are swellings along lymph vessels containing phagocytic cells (lymphocytes) that filter the lymph, removing and destroyign foreign particles and pathogens)

Question 17

Explain the makeup of blood

Answer 17

• Contains four to six liters of blood
• 55% = liquid component
  
  • plasma
    
    • aqueous mixture of nutrients, salts, repiratory gases, wastes, hormones, and blood proteins (eg. immunoglobulins, albumin, and fibronogen)
• 45% = cellular component
  
  • erythrocytes, leukocytes and platelets

Question 18

Explain Leukocytes

Answer 18

• Leukocytes = white blood cells (or WBCs)
  
  • larger than erythrocytes and serves protective function

Question 19

Explain Platelets

Answer 19

• Platelets
  
  • cell fragments that lack nuclei and are involved in clot formation
    
    • Many drugs inhibit platelet formation or adhesion to decrease clot development

Question 20

What are erythrocytes

Answer 20

• Erythrocytes
  
  • Red blood cells (RBC’s)
  • oxygen-carrying components of blood
  • contain ~250 million molecules of hemoglobin, each of which can bind up to four molecules of oxygen
    
    • When hemoglobin binds to oxygen = oxyhemoglobin
    • Primary form of oxygen transport in body
  • Have distinct disk like shape that give them increased surface area for gas exchange and greater flexibility for movement
• Erythrocytes are formed from stem cells in the bone marrow; stimulated by erythropoietin, a hormone make in the kidnesy

Question 21

What does it mean when you find immature erythrocytes circulating in the bloodstream?

Answer 21

• that is, before they have lost their organelles from the bone marrow -
• Can be an indicator of a number of disease states, such as hemolytic anemia, which is caused by a rapid destruction of red blood cells due to an infection or disorder

Question 22

Explain ABO Blood types

Answer 22

• Erythrocytes have characteristic cell-surface proteins (antigens)
  
  • Antigens = macromolecules that are foreign to the host organism and triggers an immune response
    
    • two major antigens = ABO group and the Rh Factor
• See attached for table with which Blood type has which antigen and antibody
• It is extremely important durign blood transfusions that donor and recipient blood types be appropriately matched

Question 23

What is the universal recipient of blood?

Answer 23

Type AB

has neither anti-A nor anti-B

Question 24

What is the universal Donor?

Answer 24

Type O

it will not elicit a response from the recipient’s immune system becaue it does not posses any surface antigens

Question 25

Explain the Rf factor in blood

Answer 25

• is another antigen that may be present on the surface of red bloood cells
• Rh + = possesing the Rh antigen
• Rh - = lack the Rh antigen

Question 26

Why is the Rh factor important for pregnancy?

Answer 26

• An Rh- woman can be sensitized by an Rh+ fetus if fetal red blood cells (which will have the Rf factor) enter maternal circulation during birth
• If this women subsequently carries another Rh+ fetus, the anti-Rh antibodies she produced when sensitized by the first birth may cross the placenta and destroy fetal red blood cells = erythroblastosis fetalis = severe anemia in the fetus
  
  • not caused by anti - A and anti - B because they cannot cross the placenta
  • Rhogam is a drug compreised of a mixture of anibodies given to mothers who are Rh- to prevent their immune system from attacking the fetal red blood cells

Question 27

Explain the functions of the circulatory system

Answer 27

• Transport of Gases:
  
  • Erythrocytes transport O2 throughout the circulatory system
    
    • Hemoglobin in erythrocytes bind to O2
      
      • 1 hemoglobin = 4 oxygens because of the iron
    • Hemoglobin also binds to CO2 - carbaminohemoglobin
• Transport of nutrients and waste
  
  • Amino acids and simple sugars are absorbed into bloodstream at the intestinal capillaries
  • Throughout the body, metabolic waste products (water, urea, and CO2) diffuse into capillaries from surrounding cells, deliverd to appropriate excretory organs
• Clotting
  
  • When platelets come into contact with the exposed collagen of a damaged vessel, they release a chemical that causes neighboring platelets to adhere to one another = platelet plug
  • Both the platelets and the damaged tissue release the clotting factor thromboplastin, which aid of its cofactors calcium and vitiamin K, converts the inactive plasma protein prothrombin** to its active for, **thrombin
    
    • Thrombin converts fibrinogen** (another plasma protein) into **fibrin
    • Threads of fibrin coat the damaged area and trap blood cells to form a clot
  • Fluid left after the clotting is called serum

Question 28

What is the airway passages?

Answer 28

Nose, pharynx (throat), larynx, trachea, bronchi, bronchioles and alveoli

Question 29

Where does gas exchange between the lungs and the circulatory system?

Answer 29

in very thin walls of the alveoli

which ar air-filled sacs at the terminals of the airway branches

Question 30

What are alternate functions of the respiratory system?

Answer 30

• Air over the vocal cords for the production of sound
• assists in the regulation of body pH by regulating he rate of carbon dioxide removal from the blood

Question 31

Explain what happens during ventilation

Answer 31

• Inhalation = diaphram contracts and flattens, and the external intercostal muscles contract, pushing the rib cage and chest wall up and out
  
  • Phrenic nerve innervates the diaphram causing contraction and flattening
  • action - thoracic cavity to increase volume
    
    • reduces pressure, lungs expand
• Exhalation = passive process. Lungs and chest walls are highly elastic and tend to recoil to their original position after inhalation
  
  • Diaphragm and external intercostal muscles relax and chest wall pushed inward
    
    • decreasing thoracic cavity volume, pressure increases

Question 32

What is surfactant used for in the lungs?

Answer 32

• Surfactant is a protein complex secreted by cells in the lungs to keep the lungs from collapsing by decreasing surface tension in the alveoli

Question 33

How is ventilation controlled?

Answer 33

• Regulated by neurons (referred to as the respiratory center) located in the medulla oblongata
  
  • when the partial pressure of CO2 in the blood rises, the medulla oblongata stimulates and increase in the rate of ventilation

Question 34

How are oxygen levels monitored?

Answer 34

by peripheral chemoreceptors, which indirectly stimulate the respiratory center

changes in acid-base chemistry due to kidney function can also influence ventilation

Question 35

Explain how gas is exchanged in the lungs

Answer 35

• Dense network of minute blood vessels called pulmonary capillaries surround the alveoli
• Gas exchange occurs by diffusion across the capillary walls and those of the alveoli
  
  • gas moves from the higher partial pressure to the lower partial pressure

Question 36

Explain the lung capacity diagram

Answer 36

• Total lung capacity - maximum volume of air the lungs can hold
• Tidal volume = volume of air moved during a normal resting breath , significantly less than lung capacity
• Inspiratory reserve volume = Volume of air that could be additionally inhaled into the lungs at the end of a normal, resting inhalation
• Expiratory reserve volume = the volume of air left in the lungs at the end of a normal, resting exhalation
• Vital capacity = volume of air moved during a maximum inhalation followed by a maximum exhalation
• Residual volume = even after maximum exhalation, there is always some air left in the lungs

Question 37

What are the functions of the lymphatic system?

Answer 37

• Collect excess interstitial fluid and return it to the circulatory system, maintaining the balance of body fluid
• absorb chylomicrons from the small intestine and deliver them to cardiovascular circulation

Question 38

What does hetrotrophic mean and what is an example?

Answer 38

• Heterotrophic = unable to synthesize all of their own nutrients
• humans

Question 39

What is the path for raw material digestion?

Answer 39

1. Ingested (eaten)
2. Digested (breakdown)
   
   • consists of the degredation of large molecules into smaller molecules that can be absorbed into the bloodstream and used directly by cells
     
     • Intracellular digestion: occurs within the cell, usually in membrane bound vesicles
     • Extracellular digestion: digestive process that occurs outside the cell, within a lumen or tract

Question 40

Explain the digestive tract

Answer 40

1. Oral cavity
2. pharynx
3. esophagus
4. stomach
5. small intestine
6. large intestine
7. anus
   
   • Accessory organs, such as the salivary glands, pancreas, liver and gallbladder, also play essential roles in digestion

Question 41

Explain what occurs in the oral cavity

Answer 41

• mechanical and chemical digestion of food begins
  
  • Mechanical - breakdown of large food particles into smaller particles through physical actions = mastication or churning motion
  • Chemical - enzymatic breakdown of macromolecules into smaller molecules when the salivary glands secrete saliva
    
    • salive lubricates food to facilitate swallowing and provides a solvent for food particles
    • Salive contains enzymes salivary amylase (ptyalin), which hydrolyzes starch to maltose (disaccharide)
• Creates a bolus

Question 42

What is the function of salivary amylase (ptyalin)?

Answer 42

enzyme that hydrolyzes starch to maltose (disaccharide)

Question 43

What is the function of the Esophagus in the digestive tract?

Answer 43

• Muscular tube leading from the mounth to the stomach
• Food is moved down esophagus by peristalsis
• The esophagus is closed off from the stomach by contraction of muscular structure called the lower esophageal (cardiac) sphincter
• Body of esophagus lies within the thoracic cavity, negatively pressured relative to the environment on inhalation
  
  • abdominal cavity = positive pressure
  • Therefore without normal defense mechanisms, leads to stomach acid in esophagus = aka, gastroesophageal reflux disease (GERD)

Question 44

What are the physiologic changes associated with the gastroesophageal reflux (GERD)?

Answer 44

• Reflux can occur after spontaneous transient lower esophageal sphincter relaxation not associated with swallowing
• Patients with GERD usually have a decreased lower esophageal sphincter pressure (5-10 mmHg above gatric baseline pressure), leading to an increased passage of stomach contents into esophagus
• Resting pressures of the lower esophageal sphincter normally range from 15-35 mmHg above gastric baseline pressure

Question 45

What is the function of the stomach in the digestive tract?

Answer 45

• Walls are lined by a gastric mucosa, contains gastric glands
• Mucous cells in gastric pits along the membrane secrete mucus to protect the stomach lining from the harsh acidic juices (pH = 2) in the stomach
• Chief cells found within the gastric glands synthesize pepsinogen, converted to pepsin upon contact with stomach acid and breaks down proteins
• Parietal cells, also present within gastric glands, synthesize and release HCL, which alters the pH of the stomach and kills bacteria and intrinsic factor, necessary for absorption of vitamin B₁₂
• Churning of stomach (mechanical, combinded with enzyme activity (chemical) produces acidic, semifluid mixture of partially digested food = chyme
  
  • ​passed to duodenum throug the pyloric sphincter

Question 46

Explain the function of the small intestine in digestive tract

Answer 46

• Chemical digestion is completed in the small intestine
• Divided into three section:
  
  • Duodenum
  • Jejunum
  • ilieum
• Highly adapted to absorption
  
  • to max the SA, for digestion and absorption, the intestin is extremely long and highly coiled.
  • Also contains projections called vili
    
    • contain capillaries and lacteals (vessels of the lyphatic system)
    • Amino acids and monosaccharides pass through the villi walls into the capillary system
      
      • Blood from digestive tract enters portion of liver where it is detoxified and stripped of some of its nutrients
    • Large fatty acids and glycerol pass into lacteals and are then reconverted into triglycerides in the liver
    • Note glucose and Amino Acids are actively absorbed, require energy

Question 47

Where does blood from the digestive tract enter from the small intestine?

Answer 47

• Into the liver
  
  • Amino Acids and monosaccharides pass through the villi walls into capillary system (active transport)
  • Large fatty acids and glycerol pass into the lacteals (lymphatic system vessels) and reconverted to triglyceride

Question 48

Where does most of the digestion occur in the small intestines?

Answer 48

• Duodenum, where the secretions of the intestinal glands, pancrease, liver and gallbladder mix together with the acidic chyme entering from the stomach

Question 49

What does intestinal mucosa secrete and what is it used for, digestion wise?

Answer 49

• Lipases - fat digestion
• aminopeptidase - polypeptide digestion
• disaccharideases - for maltose, lactose and sucrose digestion (eg. lactase)

Question 50

What is the function of Gastrin hormone in the digestive tract

Answer 50

• Gastin:
  
  • Primary function = stimulate histamine and pepsinogen secretion as well as increase gastric blood flow
    
    • Also stimulates parietal cells to produce HCL, which denatures proteins and activates digestive enzymes
  • Produced in the G cells of the duodenum

Question 51

What is the function of the Intrinsic factor hormone in the digestive tract

Answer 51

Intrinsic factor:

• Secretion of the parietal cells
• Function = facilitate the absorption of vitabmin B₁₂ across the intestinal lining

Question 52

What is the function of the Cholecystokinin (CCK) hormone in the digestive tract

Answer 52

Cholecystokinin (CCK):

• Produced and stored in the I cells of the duodenal and jejunal mucosa
• Function = stimulation of pancreatic enzymes and somatosatin secretion as well as gallbladder contraction
  
  • acts as a hunger suppressant

Question 53

What is the function of the Secretin hormone in the digestive tract

Answer 53

Secretin:

• Synthesized and stored in the S cells of the upper intestine
• Function = stimulates the secretion of bicarbonate-containing substances from the pancrease and inhibits gastric emptying and gastric acid production

Question 54

What is the function of the liver in the digestive system?

Answer 54

• Produces bile that is stored in the gallbladder before being released into the small intestine
  
  • bile contains no enzymes; it emulsifies fats, breaks down large globules into small droplets
    
    • Emulsification of fat exposes a greater surface area of the fat to the action of pancreatic lipase
• Additional functions = storage of glycogen, converstion of ammonia to urea, protein synthesis, detoxification and cholesterol metabolism

Question 55

What occurs in the absence of bile in the digestive system?

Answer 55

fats cannot be digested

Question 56

What is the function of the pancrease in the digestive system?

Answer 56

• Produces enzymes such as:
  
  • amylase = carbohydrate digestion
  • trypsin = protein digestion
  • lipase = fat digestion
• When the pancrease releases chymotrypsin and enterokinase, enterokinase cleaves trypsinogen into trypsin
  
  • Trypsin then cleaves and activates the other zymogens (enzyme precursors)
• Pancrease secretes a bicarbonate-rich juice that neutralizes acidic chyme from stomach
• Pancrease opperates optimally at this higher pH

Question 57

What is the function of the large intestine in the digestive system?

Answer 57

approximately 1.5 m long and absorbs salts and any water not already absorbed by the small intesting

Rectum provides for transient storage of feces before elimination through the anus

Question 58

What does deamination produce for metabolic waste and where?

Answer 58

Deamination of amino acids in the liver leads to the production of nitrogenous wastes, such as urea and ammonia

Question 59

What are the principal organs of excretion in humans? explain each

Answer 59

• lungs
  
  • CO₂ and H₂O vapor diffuse from the blood and are continually exhaled
• liver
  
  • processes nitrogenous wastes, hemoglobin and other chemicals for excretion
  • Urea is produced by the deamination of amino acids in the liver and diffuses into the blood for ultimate excretion in the kidnesy
• skin
  
  • excrete H₂O and dissolved salts (urea)
  • perspiration serves to regulate body temperature since the evaporation of sweat removes heat from the body
• kidnesy
  
  • functions to maintain the osmolarity of the blood, excrete numerous waste products and toxic chemicals and conserve glucose, salt and water
  • Bile salts are excreted as bile and pass out with the feces

Question 60

Explain the kidney’s overall function and location

Answer 60

• Function = regulate the concentration of salt and water in the blood through the formation and excretion of urine
• Location/description = bean-shaped and located behind the stomach and liver
  
  • each kidney is composed of approximately one million units called nephrons

Question 61

Explain the structure of the kidney

Answer 61

• Kidney is divided into three regions:
  
  • outer cortex
  • Inner medulla
  • renal pelvis
• Nephron consists of:
  
  • bulb = bowman’s capsule = embraces a special capillary bed called a glomerulus
  • Bowman’s capsule leads to a long, coiled tube divided into funcionally distinct units:
    
    • proximal convoluted tubule (cortex)
    • Loop of Henle (medulla)
    • distal convoluted tubule (cortex)
    • collecting duct (medulla)
  • Most of nephron is surrounded by a complex peritubular capillary network that facilitates reabsorption of amino acids, glucose, salt and water

Question 62

Explain the steps to Urine Formation

Answer 62

1. Filtration:
   
   • Blood pressure forces 20% of blood plasma to glomerulus through capillary walls into Bowman’s capsule
     
     • Fluid and small solutes entering = filtrate (isotonic with blood plasma)
       
       • Passive process driven by hydrostatic pressure of blood
         
         • high BP = high hydrostatic P and can lead to kidney damage overtime
2. Secretion:
   
   • nephron secretes waste substances such as acids, ions and other metabolites from the interstitial fluid into the filtrate by passive and active transport
3. Reabsorption:
   
   • Essential substances (glucose, salts and amino acids) and water are reabsorbed from the filtrate and returned to the blood
     
     • primarily occurs in proximal convoluted tubule and is an active process (water passive process)
       
       • forms concentrated urine, hypertonic to the blood

Question 63

Which particles are too large to filter through the glomerulus?

Answer 63

blood cells and albumin which remain in the circulatory system

Question 64

What is the primary function of the nephron?

Answer 64

clean the blood plasma of unwanted substances as the filtrate passes through the kidney

Question 65

Where is the primary site of nutrient reabsorption in the nephron?

Answer 65

proximal convoluted tubule

Question 66

What function does the loop of henle and collecting duct play?

Answer 66

regulation of water, sodium and potassium concntrations in the nephron

Question 67

What is the function of the distal confoluted tubule?

Answer 67

major site for secretion of substances into the filtrate

Question 68

Explain each part of the loop of Henle

Answer 68

• Each part plays a distinct role in regulating water absorption and electrolyte concentration
• Descending = very permeable to water, but not to ions or urea
• Ascending =
  
  • thin = impermeable to water but permeable to ions, allowing for passive diffusion of ions
  • thick = sodium, potassium and chloride are actively reabsorbed from the urine

Question 69

Explain the osmolarity gradient that allows for the production of concentrated urine

Answer 69

• Osmolarity gradient between the tubules and the interstitial fluid surrounding them
• By exiting and re-entering at different segments of the nephron, solutes such as Na+ and Cl-, create this osmolarity gradient, with tissue osmolarity increasing from the cortex to the inner medulla
  
  • gradient depends on the counter-current-multiplier system
    
    • system in which energy is used to create a concentration gradient

Question 70

Explain the counter-current multiplier on the kidney, what hormone regulates it?

Answer 70

• Causes the interstitial space in the medulla to be hyperosmolar with respenct to the dilute filtrate in the renal tube
  
  • filtrate travels down the collecting ducts to pelvis and ureter
  • water flows from the ducts to the interstitial fluid through osmosis
• The reabsorption zone of H2O in the kidneys depends on the permeability of the collecting ducts to water
  
  • regulation of the permeability of the ocllecting ducts to water is accomploished by antidiuretic hormone (ADH) = vasopressin
    
    • ADH increases =increase permeability of collecting ducts to H2O,
      
      • more water to be absorbed and higher urine concentration
        *

Question 71

Explain the two hormones that impact urine formation in the kidneys

Answer 71

• Aldosterone:
  
  • causes increased transport of sodium and potassium ions along the distal convoluted tubule and collecting duct
    
    • results = decreased excretion of Na+ and increased excretion of K+ in urine
      
      • additional water reabsorption
• Antidiuretic hormone (ADH):
  
  • same effect, increased water reabsorption
  • ADH directly affects water absorption by the distal convoluted tubules and collecting ducts, opening additional aquaporins (water channels) allowing water to reabsorbed more readily

Both Aldosterone and ADH cause a decrease in urine output and increase in blood pressure, allowing human body to compensate for periods of dehydration or other causes of low blood pressure

Question 72

What are diuretics?

Answer 72

drugs that target different parts of the kidneys to cause an increase in urine production

increaseing the amount of water preent in the urine and therefore increasing urine secretion

Question 73

Explain the maintenance of pH

Answer 73

• pH remains relatively constant at 7.4
  
  • removal of CO2 by the lungs and hydrogen ions by kidneys

Question 74

What laboratory tests for pH

Answer 74

• arterial pH
• arterial partial pressure of carbon dioxide (P_co2)
• plasma bicarbonate (HCO₃^-)

Question 75

What are two types of acid-base disorders, name and describe

Answer 75

1. Respritory: affects the blood acidity by causing changes in the P_co2
   
   • ​​Compensation performed by respiratory system
2. Metabolic: affects the blood acidity by causing changes in the HCO₃^-
   
   • ​​Compensation performed by kidneys
     
     • therefore take long time

Question 76

Which region of the kidney has the lowest solute concentration?

Answer 76

Cortex

Question 77

In the nephron, amino acids enter the peritubular capillaries via?

Answer 77

reabsorption

Question 78

Glucose reabsorption in the nephron occurs in the?

Answer 78

proximal tubule

Question 79

Urin is ______ to blood?

Answer 79

hypertonic

Question 80

What is the difference between Endocrine glands and Exocrine glands?

Answer 80

• Endocrine glands = synthesize and secrete chemical substances called hormones directly into the circulatory system
• Exocrine glands = such as the gallbladder, secrete substances trensported by ducts

Question 81

Name the endocrine glands

Answer 81

1. pituitary
2. hypothalamus
3. thyroid
4. parathyroid
5. adrenal
6. pancrease
7. testes
8. ovaries
9. pineal gland
10. kidneys
11. gastrointestinal glands
12. heart
13. thymus

Question 82

Explain where the adrenal glands are and the overall components of it?

Answer 82

• Location: on top of the kidneys
• Consist of:
  
  • Adrenal cortex
  • Adrenal medulla

Question 83

Explain the main way the Adrenal cortex responds to stress

Answer 83

• In response to stress, adrenocorticotropic hormone (ACTH), produced in the anterior pituitary, stimulates the adrenal cortex to produce more than two dozen different steroid hormones, collectively known as adrenocortical steroids (or corticosteroids):
  
  • There are three major classes of corticosteroids:
    
    • Glucocorticoids
    • Mineralocorticoids
    • Cortical sex hormones

Question 84

In the bloodstream what is corticosteroids bound to?

Answer 84

bound to transport proteins called transcortins

Question 85

Explain Glucocorticoids

Answer 85

Adrenal cortex

• such as cortisol** and **cortisone, involved in glucose regulation and protein metabolism
  
  • raise blood glucose levels by promoting protein breakdown and gluconeogenesis
    
    • ​decreasing protein synthesis
  • glucocorticoids are antagonistic to the effects of insulin
  • release amino acids from skeletal muscles as well as lipids from adipose tissue
  • permote the peripheral use of lipids and have anti-inflammatory effects

Question 86

Explain Mineralocorticoids

Answer 86

Adrenal Cortex

• Aldosterone, regulate plasma levels of sodium and potassium and the total extracellular fluid volume
  
  • Aldosterone causes active reabsorption of sodium and passive reabsoprtion of water in the nephron of kidney
    
    • increase in blood volume and blood pressure
    • Excess aldosterone = excess retention of water, hypertension (high blood pressure)
• Mineralocorticoids are stimulated by angiotension II and inhibited by ANP (atrial natriuretic peptide)

Question 87

Explain Cortical sex hormones

Answer 87

Adrenal Cortex

• In both men and women, AC secretes small quantities of androgens (male sex hormones) like androstenedione and dehydroepiandrosterone
  
  • In men, most androgens are produced by testes, so the physiologic effect of the andrenal androgens is quite small
  • Women, however, overproduction of adrenal androgens may cause excess facial hair, etc.

Question 88

What is the adrenal medulla responsible for?

Answer 88

• “Fight or flight”
• Two hormones:
  
  • Epinephrine (adrenaline)
    
    • ​Increases the conversion of glycogen to glucose in liver and muscle tissue, increase in blood glucose and basal metabolic rate
  • Norepinephrine (noradrenaline)
  • Both:
    
    • increase rate and strength of the heartbeat and dilate and constrict blood vessels,
      
      • increase blood supply to skeletal muscles, heart and brain
      • decrease blood supply to kidneys, skin and digestive tract
    • promote release of lipids by adipose tissue
    • also neurotransmitters
• Both of which belong to the class of amino acid-derived compounds called catecholamines

Question 89

Explain the Pituitary gland

Answer 89

• The pituitary (Hypophysis) is a small, trilobed gland at the base of the brain
• two main lobes:
  
  • Anterior
  • Posterior
• Hangs below the hypothaamus and is connected to it by a slender cord = infundibulum

Question 90

Explain the Anterior pituitary function

Answer 90

• Synthesizes both:
  
  • direct hormones - directly act on target organs
  • tropic hormones - stimulate other endocrine glands to release hormones
• Hormonal secretion of the anterior pituitary are regulated by hypothalamic hormones = releasing/inhibiting hormones or factors

Question 91

What are the direct hormones that the anterior pituitary produces (name and describe)?

Answer 91

Direct hormones - direct effect

• Growth hormones (GH, somatotropin):
  
  • Promotes bone and muslce growth
  • promotes protein synthesis and lipid mobilization and catabolism
  • deficiency - dwarfism, over production = gigantism
    
    • adults over production = acromegaly
• Prolactin:
  
  • stimulates milk production in female mammary glands

Question 92

What are the tropic hormones that the anterior pituitary produces (name and describe)?

Answer 92

tropic = stimulate other endocrine glands

• Adrenocorticotropic hormone (ACTH):
  
  • stimulates adrenal cortex to synthesize and secrete glucocorticorids and regulate corticotropin-releasing factors (CRF)
• Thyroid-stimulating hormone (TSH):
  
  • stimulates thyroid gland to synthesize and release thyroid hormone, including thyroxin
• Lutenizing hormone (LH):
  
  • Women: stimulates ovulation and maintenance of corpus luteum and regulates progesterone secretion
  • Men: stimulates interstitial cells of testes to synthesize testosterone
• Follicle-stimulating hormone (FSH):
  
  • Women: maturation of ovarian follicles, turn secrete estrogen
  • Men: maturation of the seminiferous tubules and sperm production
• Melanocyte-stimulating hormone (MSH):
  
  • secreted by intermediate lobe of pituitary. Mammals function unclear, darkening of skin pigment melanophore cell dispersion
• Endorphins:
  
  • neurotransmitters that help pain-relieving properties

Question 93

Describe the posterior pituitary and its hormones

Answer 93

• The posterior pituitary (neurohypophysis) does not synthesize hormones; it stores and releases the peptide hormones:
  
  • Oxytocin:
    
    • secreted during childbirth, increases the strenth and frequency of uterine muscle contractions
    • stimulates milk secretion in mammary glands
  • Antidiuretic hormone (ADH, vasopressin):
    
    • increases the permeability of the nephron’s collecting duct to water
      
      • promoting water reabsorption, increase blood volume, increases blood pressure
    • Secreted when plasma osmolarity increases, sensed by osmoreceptors in hypothalamus,
      
      • or when blood volumes decreased, sensed by baroreceptors in the circulatory system
• Which are both produced by the neurosecretory cells of the hypothalamus
• hormone secretion is stimulated by action potentials descending from the hypothalamus

Question 94

Explain the hypothalamus

Answer 94

• part of forebrain and located directly above the pituitary gland
• receives neural transmission from ther parts of the brain and from peripheral nerves, triggering response from neurosecretory cells
  
  • these cells regulate pituitary gland secretion via negative feedback and inhibiting/releasing hormones

Question 95

Explain the function of GnRH

Answer 95

stimulates the anterior pituitary to secrete FSH and LH

Question 96

Explain the feedback when plasma levels of adrenal cortical hormones drop

Answer 96

1. hypothalamic cells (via a negative feedback mechanism) release corticotropin-releasing factor (CRF) into the portal system, which signals the pituitary cells to release ACTH
2. ACTH then acts on the adrenal cortex to increase glucocorticoid levels
3. when the plasma concentration of corticosteroids exceeds the normal plasma level the steroids themselves exert an inhibitory effect on the hypothalamus

Question 97

Explain the hypothalamus interaction with the posterior pituitary

Answer 97

Neurosecretory cells in the hypothalamus synthesize both oxytocin and ADH and transport them via their axons into the posterior pituitary for starage and secretion

Question 98

Explain the thyroid gland

Answer 98

• Thyroid hormones affect the function of nearly every organ system in the body
  
  • children, these hormones are essential for growth and neurological development
  • adults, hormones increase the rate of metabolism throughout the body and maintenance of metabolic stability

Question 99

What are the thyroid hormones, name and describe

Answer 99

• Thyroxine (T4)
• Triiodothyronine (T3)
• Calcitonin: “tones the bone”
  
  • ​antagonist to parathyroid hormone (PTH)
• T4 and T3 formed from glycoprotein thyroglobulin, synthesized in thyroid cells

Question 100

Explain the characteristics between thyroxine (T4) and triiodothyronine (T3) hormones of the thyroid

Answer 100

• T3 is 5 times more potent than T4
• T4 and T3 are transported via plasma proteins
• All of the T4 in the body is formed and secreted by the thyroid gland; however, 20% of T3 is produced by the thyroid gland
• The majority of T3 is produced by conversion of T4 to T3 by the enzyme 5’-monodeiodase, found primarily in the peripheral tissues

Question 101

Explain the common issues/illnesses with thyroid

Answer 101

• Hypothyroidism = thyroid hormones are undersecreted or not secreted at all
  
  • Symptoms = slowed heart rate, respiratory rate slowed, fatigue, cold intolerance, weight gain
  • Infants = cretinism - mental retardation and short stature
• Hyperthyroidism = thyroid is overstimulated, over secretion of thyroid hormones
  
  • Symptoms = increased metabolic rate, feels of excessive warmth, profuse sweating, palpitations, weight loss, and protruding eyes

Both normally due to a thyroid enlarged, formoing a bulge in the neck called a goiter

Question 102

Explain the function of the pancrease in the endocrine system

Answer 102

• The pancrease is both an exocrine organ and an endocrine organ
  
  • exocrine function = performed by the cells that secrete digestive enzymes into the small intestine via series of ducts
  • endocrine function = performed by small glandular structures called the islets of Langerhans, alpha and beta cells
    
    • alpha cells = glucagon
    • beta cells = insuline

Question 103

Name and describe the function of the pancreas hormones

Answer 103

• Glucagon
  
  • stimulates protein and fat degradation, conversion of glycagen to glucose, and gluconeogenesis = increase blood glucose
  • antagonist to insulin
• Insulin
  
  • stimulates uptake of glucose by muscles and adipose cells and storage of glucose as glycagen in muscles and liver cells = lowering blood glucose
  • Stimulates synthesis of fats from glucose and uptake of amino acids
  • antagonistic to glucagon and glucocorticoids

Question 104

Explain diabetes mellitus

Answer 104

underproduction of insulin, or insensitivity to insulin

= hyperglycemia (high blood glucose levels)

Question 105

Explain the difference between type I and type II diabetes

Answer 105

see attached

Question 106

Explain the parathyroid glands

Answer 106

• Four small, pea-shaped structures embedded in the posterior surface of the thyroid
• Synthesize and secrete parathyroid hormone (PTH), which regulates plasma Ca2+ concentration
• PTH raises the Ca2+ concentration in the blood by breaking down bone and decreasing Ca2+ excretion in the kidneys
• Calcium is bound to phosphate in bone, PTH compensates for the increase in phosphate by stimulating excretion of phosphate by the kidneys

Question 107

Explain the kidneys as an endocrine system

Answer 107

• When blood volume falls, the kidneys produce renin
  
  • enzyme that converts plasma protein angiotensinogen to angiotensin I
    
    • Angiotensin I is converted to angiotensin II, stimulates the adrenal cortex to secrete aldosterone
      
      • Aldosterone = helps restore blood volumes by increasing sodium reabsorption by kidneys = increased fluid retention
• Kidneys also produce erythropoietin (EPO)
  
  • glycoprotin that stimulates red blood cell production

Question 108

What does erythropoietin (EPO) cause?

Answer 108

stimulates red blood cell production, produced in the Kidneys

• Stimulation of the stem cells to differentiate into rubriblasts (least mature erythrocytes)
• Increased rate of mitosis
• Increased release of reticulocytes from the bone marrow
• Increased hemoglobin (HgB) formation, which results in the critical HgB concentration necessary for RBC maturity to be reached at a more rapid rate

Question 109

Explain the gastrointestinal hormones in the endocrin system

Answer 109

• Ingestion of food stimulates the stomach to release the hormone gastrin
  
  • carried to the gastric glands and stimulates the glands to serete HCL
• The hormone secretin is released by the small intestine when acidic chyme enters from the stomach
  
  • stimulates the secretion of an alkaline bicarbonate solution from the pancrease that neutralizes the acidity of the chyme
• The hormone cholecystokinin is released by the small intestine in response to the presence of fats and causes the contraction of the gallbladder and release of bile into the small intestine
  
  • bile, not a hormone, involved in emulsification and digestion of fat

Question 110

Explain the pineal gland endocrin system structure

Answer 110

• Pineal gland is a tiny structure at the base of the brain
  
  • secretes melatonin
    
    • circadian rhythms

Question 111

Explain how peptide hormones affect the activity of their target cells (via extracellular receptors or intracellular receptors)

Answer 111

• range from simple short peptides (amino acid chains), such as ADH, to complex polypeptides, such as insulin
• Peptide hormones = first messanger, bind to receptors, trigger a series of enzymatic reactions
  
  • converstion of ATP to cyclic adenosine monophosphate (Cyclin AMP)
  • Cyclic AMP acts as secondary messenger
    
    • relays message from extracellular peptide to cytoplasmic enzymes
    • Cascade effect with each stop, amplifying effect

Question 112

Explain how steroid hormones affect the activity of their target cells (via extracellular receptors or intracellular receptors)

Answer 112

• such as estrogen and aldosterone = lipid derived molecules with ring structure
• Cross the phospholipid bilayer and enter their target cells directly with a receptor molecule
  
  • receptor-hormone complex enters the nucleus and directly activates the expression of specific genes by binding to receptors on the chromatin

Question 113

Thyroid hormone deficiency may results in …….?

Answer 113

cretinism

Question 114

T/F: growth hromone promotes protein synthesis?

Answer 114

False!!!!

Question 115

What does sexual reproduction require?

Answer 115

• The production of functional sex cells or gametes by adult organisms
• The union of these cells (fertilization or conjugation) to form a zygote
• The development of the zygote into another adult, completing the cycle

Question 116

Explain Gonads

Answer 116

• Gametes produced in specialized organs called gonads
  
  • Male gonads = testes, produce sperm in the tightly coiled seminiferous tubules
  • Female gonads = ovaries, produce oocytes (eggs)

Question 117

What are hermaphrodites

Answer 117

possess both functional male and female gonads

these include the hydra and the earthworm

Question 118

Explain the gametogenesis of males and females

Answer 118

• Gametogensis = production of functional sex cells
• Males = spermatogenesis
  
  • sperm production, and occurs in the seminiferous tubules of the testes
• Females = oogenesis
  
  • egg production, and occurs in the ovaries

Question 119

Explain the male reproductive system, including the sperm path from the testes

Answer 119

• Testes are located in the scrotum - external pouch that maintains the testes’ temperature at 2degC to 4degC lower than body temperature, a condition essential for sperm survival
• Sperm path from the testes:
  
  • from testes, through the vas deferens to the ejaculatory duct, then to the urethra
    
    • The urethra passes through the penis until it terminates with an external opening at the glans of the penis

Question 120

Explain spermatogenesis

Answer 120

Spermatogenia -> primary -> secondary -> spermatid -> spermatazoa

• Spermatogenesis, or sperm production
  
  • occurs in the seminiferous tubules
• Diploid cells called spermatogenia differentiate into diploid cells called primary spermatocytes, which undergo a meiotic division to yield two haploid secondary spermatocytes of equal size; a second meiotic division produces four haploid spermatids of equal size
• After meiosis the spermatids undergo a final series of changes that increase their mobility, resulting in mature sperm, or spermatozoa

Question 121

Explain the structure of a sperm

Answer 121

elongated cell with a head, neck, body and tail

• Head - nucleus
• tail (flagellum) propels the sperm, while mitochondria in the neck and body provide energy for locomotion
• A caplike structure called the acrosome, derived from the golgi apparatus, develops over the anterior half of the head
  
  • contains enzymes needed to penetrate the though outer covering of the ovum

Question 122

Explain the female reproductive system

Answer 122

• Ovaries consist of thousands of follicles
  
  • Follicle = multilayered sac of cells that contain, nourishes, and protects an immature ovum
  • Follicle cells produce estrogen
  • Once a month an immature follicle is released and travels via cilia into the oviduct (fallopian tube)
    
    • fallopian tube opens into the uterus, site of fetal development
    • Lower narrow end of the uterus= cervix that connects to the vaginal canal
      
      • vaginal canal is the site of sperm deposition during intercourse

Question 123

Explain the Oogenesis

Answer 123

Primary oocytes -> after menarche -> secondary oocytes -> Mature with two layers

• Oogenesis = production of female gametes
  
  • occurs in the ovarian follicles
• At birth, most of the immature ova (primary oocytes) that the female will produce is already formed
  
  • Primary oocytes = diploid
    
    • formed by mitosis in the ovary
  • After menarche (first female menstration), one primary oocyte per month completes meiosis I, yeilding two daughter cells of unequal size = secondary oocyte and a small cell = polar body
    
    • secondary oocyte is expelled from follicle during ovulation
      
      • Meiosis II does not occur until fertilization
• The oocyte cell is surrounded by two layers
  
  • inner zona pellucida layer
  • outer corona radiata layer
    
    • Meiosis II is triggered when these layers are penetrated by a sperm, yielding two haploid (mature ovum and polar body)

Question 124

Explain the female sex hormones

Answer 124

• The secretion of both estrogens and progestersons in the ovaries is regulated by luteinizing hormone (LH) and follicle stimulating hormone (FSH), which are regulated by honadotropin-releasing hormone (GnRH)
  
  • Estrongen: secreted by ovarian follicles and corpus luteum
    
    • Steroid hormones for normal female maturation
    • Stimulate development of female reproductive tract, contriute to development of secondary sexual characteristics, and influence libido
    • Responsible for thickening of the endometrium (inner lining of the uterine walls)
  • Progesterone: secreted by the corpus luteum
    
    • steroid hormone secreted during the luteal phase of the menstrual cycle
    • Stimulates the development and maintenance of the endometrium in preparation for implantation

Question 125

What endocrine organs play roles in the female menstral cycle?

Answer 125

ovaries, hypothalamus and anterior pituitary

Question 126

Explain the steps of the menstral cycle

Answer 126

1. Folliclar phase
   
   • Begins when menstrual flow from previous cycle stops
   • During phase, FSH from anterior pituitary promotes development of follicle, which grows and begins secreting estrogen
2. Ovulation
   
   • Midway through cycle a mature ovarian follicle bursts and releases an ovum
   • Surge in LH due to peak in estrogen level
3. Luteal phase
   
   • LH maintains the remnant of the ruptured follicle, called the corpus luteum, which secretes estrogen and progesterone
   • Progesterone causes the glands of the endometrium to mature, prepare for embryo implantation
     
     • Progesterone and estrogen are essential for maintenance of endometrium
4. Menstration
   
   • If ovum is not fertilized, the corpus luteum atrophies
     
     • Resulting in a drop of progesterone and estrogen levels causing endometrium to slough off = menstrual flow (menses)
   • If ovum is fertilized, the developing placenta produces hCG (human chorionic gonadotropin), maintaining the corpus luteum and supply of estrogen and progesterone
     
     • eventually placenta will take over production of these hormones

Question 127

Explain where fertilization occurs

Answer 127

• An egg can be fertilized during the 12-24 hours after ovulation
• occurs in the lateral, widest portion of the fallopian tube
  
  • sperm travels through the vaginal canal, cervix, uterus, and into fallopian tubes to reach the ovum
    
    • Sperm remains viable for fertilization for 1-2 days after intercourse

Question 128

Explain how fertilization occurs, sperm penetration of the ovum

Answer 128

• Layers:
  
  • Sperm must first penetrate corona radiata
    
    • enzymes secreted by sperm aid in penetration of this layer
  • Sperm then penetrate the zona pellucida, using acrosome,
    
    • releases enzymes that digest this layer
• Once in contact with ovum cell membrane, sperm forms a tube like structure called the acrosomal process, fusing sperm cell membrane with ovum
  
  • sperm nucleus now enters the ovum’s cytoplasm and completes meiosis II
• Acrosomal reaction triggers a cortical reaction in the ovum
  
  • causes calcium ions to release into cytoplasm = formation of the fertilization membrane
    
    • membrane - hard layer prevents multiple fertilizations
  • Calcium also stimulates metabolic changes in ovum, increasing metabolic rate = first mitotic division of the zygote soon follows

Question 129

Explain multiple births - monozygotic (identical) twins

Answer 129

• Result when a single zygote splits into two embryos
  
  • of splitting occurs at the two-cell stage of development, embryos will separate chorions and separate placentas
  • If occurs at blastula stage, embryos will have one chorionic sac and share placenta and possibly an amnion
• Same zygote = Same sex, blood type and so on

Question 130

Explain multiple births - Dizygotic (fraternal) twins

Answer 130

• Two ova are released in one ovarian cycle and fertilized by two different sperm
  
  • two embryos implant into uterine wall individually
  • Each with own placenta, amnion, and chorion
• Two distinct zygotes

Question 131

Upon ovulation, the oocyte is released into the?

Answer 131

abdominal cavity

which then the cilia in the fallopian tube direct it into there

Question 132

What are the gland in the male reproductive system?

Answer 132

prostate, bulbourethral (Cowper’s) gland, seminal vesicles

Question 133

What is another name for the adrenal glands

Answer 133

suprarenal glands

Question 134

Explain early embryonic development

Answer 134

• Characterized by a series of rapid mitotic divisions = cleavage
  
  • lead to an increase in cell number without a corresponding growth in cell protoplasm (total volume of cytoplasm remains constant)
    
    • Therefore, cleavage is progressively smaller cells with an increasing ratio of nuclei to cytoplasm
      
      • ​increase in surface to volume ratio
• ​First cleavage = 32 hours after fertilization
• Second = 60 hours
• Third = 72 hours
  
  • eight celled embryo reaches the uterus
• mortula forms into blastula (series of steps)
  
  • mortula, blastulation after murtula forms blastocole, blastula
    
    • blastula implants into uterus

Question 135

Explain the steps of the blastula formation

Answer 135

• A solid ball of embryonic cells, mortula, is formed
• Blastulation begins when the mortula develops a fluid-filled cavity called the blastocoel, which by the fourth day becomes a hollow sphere of cells called the blastula
  
  • blastula implants into the uterus

Question 136

Explain the steps of gastrulation fetal development

Answer 136

• After two weeks, the embryo is fully implanted in the uterus and cell migration transform the single cell layer of blastula into a three-layerd structure = gastrula
  
  • three germ layers
    
    • Extoderm
    • Endoderm
    • Mesoderm

Question 137

What makes up the Extoderm Gastrulation layer

Answer 137

• intergumentary system
  
  • (epidermis, hair, nails, and epithelium of nose, mouth and anal canal)
• Lenses of the eye
• retina
• nervous system

Question 138

What makes up the Endoderm Gastrulation layer

Answer 138

• epithelial linings of the digestive and respiratory tracts (including the lungs)
• Part of the liver, pancrease, thyroid and bladder lining

Question 139

What makes up the Mesoderm Gastrulation layer

Answer 139

• Musculoskeletal system
• circulatory system
• excretory system
• gonads
• connective tissues throughout the body
• portions of digestive and respiratory organs

Question 140

What is neurulation

Answer 140

• by the end of gastrulation, regions of the germ layers begin to develo into a rudimentary nervous system
• starts before week three

Question 141

Explain the development of the neural tube

Answer 141

• A rod of mesodermal cells develop, notochord, along the longitudinal axis of the embryo, just under the dorsal layer of ectoderm
• Notochord has an inductive effect on the overlaying ectoderm, causing it to bend inward
  
  • form a groove along the dorsal surface of embryo
• Dorsal extoderm folds on either side of the groove; these neural folds grow upward and finally fuse, forming a closed tube
  
  • This neural tube, gives rise to the brain and spinal cord (central nervous system)
    
    • once neural tube is formed, it detaches from surface of ectoderm

Question 142

Explain the cells at the tip of each neural fold

Answer 142

called neural crest cells

• These cells migrate laterally and give rise to many components of the peripheral nervous system
  
  • Sensory ganglia
  • autonomic ganglia
  • adrenal medulla
  • schwann cells

Question 143

What is it called when the neural tube does not close properly? how can it be prevented?

Answer 143

Spina bifida

mother takes _folic acid supplement_s during pregnancy

Question 144

Explain the three different components that continue even after gestation of fetal development

Answer 144

• Organogenesis:
  
  • Body organs begin to form
  • In this process, the cells interact, differentiate, change physical shape, proliferate and migrate
• Growth:
  
  • Organs increase in size
    
    • continual process from infancy through childhood to adulthood
• Gametogenesis:
  
  • Egg develop in wome and sperm develop in men, permits reproduction to occur

Question 145

Explain a brief overview of placental development

Answer 145

• Fetus receives oxygen and removes metabolic wastes and CO2 through mother in a specialized circulatory system
  
  • Two components:
    
    • Placenta
    • Umbilical cord
      
      • both develop in the first few weeks after fertilization

Question 146

What makes up the placenta and the umbilical cord

Answer 146

• They are outgrowths of the four extra-embryonic membranes formed during development:
  
  • amnion
  • chorion
  • allantois
  • yolk sac

Question 147

Explain the function of the amnion

Answer 147

• thin, tough membrane containing a watery fluid called the amniotic fluid
• acts as a shock absorber of external pressure during gestation and localized pressure from uterin contractions during labor

Question 148

What does the placenta formation begin with?

Answer 148

chorion

Question 149

Explain the chorion

Answer 149

• Where placenta formation begins
• a membrane that completely surrounds the amnion
• assists with transfer of nutrients from mother to fetus

Question 150

What is the function of the allantois

Answer 150

• Third placental membrane
• develops as an outpocketing of the gut
• Blood vessels of the allantoic wall enlarge and become the umbilical vessel, which will connect the fetus to the developing placenta

Question 151

Explain the yolk sac

Answer 151

• Site of early development of blood vessles
• becomes associated with the umbilical vessels

Question 152

What occurs during the first trimester?

Answer 152

• First weeks:
  
  • major organs begin to develop
    
    • heart begins beating at 22 days
    • eyes, gonads, limbs and liver start to form
• by 5th week:
  
  • 10 mm long
• 6th weeks
  
  • 15 mm long
• 7th week
  
  • Cartilaginous skin begins to turn to bone
• 8 week
  
  • most of the organs have formed, brain is fairly developed
  • embryo = fetus
• End of ninth week: 9 cm long

Question 153

What occurs during the second trimester?

Answer 153

• Fetus does a tremendous amount of growing
• Begins to move around in the amniotic fluid
• Face appears human
• toes and fingers elongate
• end of sixth month, fetus 30-36 cm long

Question 154

What occurs during the third trimester?

Answer 154

• Seventh and eighth months
  
  • rapid growth and further brain development
• Ninth month, antibodies are transported by highly selective active transport from mother to baby
• Growth rate slows and fetus becomes less active as less room to move

Question 155

What occurs during birth and maturation

Answer 155

• child birth is from labor
  
  • series of strong uterine contractions
• Three stages of labor:
  
  1. cervix thins and dialates and the amniotic sac ruptures releasing fluid
     
     • contractions are relatively mild
  2. Rapid contraction period
     
     • resulting in the birth of the baby
       
       • Umbilical cord cut
  3. Uterus contract, expelling the placenta and the umbilical cord

Question 156

Explain types of congenital disorders

Answer 156

aka birth defects

• Chemical and biological agents that cause disorders = teratogens
  
  • some drugs, such as alcohol and tobacco, and some microorganisms such as viruses and bacteria

Question 157

Explain vertical transmission

Answer 157

mother passes on an infection directly to her developing offspring

can occur either during development or birth

Question 158

Explain the process of seed formation and parts

Answer 158

• The zygote divides mitotically to form the mass of cells called the embryo
• Embryo consists of the following parts:
  
  • Epicotyl
    
    • Precursor of the upper stem and leaves
  • Cotyledons
    
    • Seed leaves, dicots have two seed leaves, while monocots have only one
  • Hypocotyl
    
    • lower stem and root
  • Endosperm
    
    • feeds the embryo; in dicots, the cotyledon absorbs the endosperm
  • Seed Coat
    
    • develops from the outer covering of the ovule, the embryo and its sead coat together comprises the seed

Question 159

Explain seed dispersal

Answer 159

• The fruit in which the seed develop is formed from the ovary walls, the base of the flower, and other consolidated flower pistil components
  
  • serves as a means of seed dispersal

Question 160

What constricts plant height?

Answer 160

growth in higher plants is restricted to the embryonic (undifferentiated) cells called meristem cells

Gradually, the cells elongate and differentiate into cell types characteristic of the species

Question 161

What are the two types of meristem cells

Answer 161

• Meristem cells = embryonic (undifferentiated) cells
  
  1. Apical meristem
     
     • found in the tips of roots and stems
     • growth in length occurs only at these points
  2. Lateral meristem (Or cambium)
     
     • Located between the xylem and phloem
     • Permits growth in diameter and can differentiate into new xylem and phloem cells
     • It is not an active tissue in monocots (grasses) or herbaceous dicots (alfalfa) but is predominant in woody dicots like oak

Question 162

Which of the following developmental stages has the greatest nuclear-to-cytoplasmic material ratio?

Answer 162

blastula

Question 163

What germ layer does the thyroid develope from?

Answer 163

Endoderm

Question 164

Define a reflux

Answer 164

automatic responses to simple stimuli and are recognized as reliable behavioral responses following a given environmental stimuli

Question 165

What is a simple reflux?

Answer 165

controlled at the spinal cord, connecting a two-neuron pathway from the receptor (afferent neuron) to the motor (efferent neuron)

• Efferent innervates the effector (muscle or gland)

Question 166

What is reticular activation system

Answer 166

• like a startle response in a complex reflex, it involved the integration of many neurons in a system
  
  • responsible for sleep-wake and behavioral motivation

Question 167

What is normal autonomic response to the stimulus that serve no useful purpus since the stimulus becomes a part of the background environment; thus, the response to the stimulus is suppressed

Answer 167

Habituation

suppression of the normal start response to stimuli

Question 168

What is it called when the stimulus is no longer regularly applied and the response recovers over time?

Answer 168

Spontaneous recovery

Question 169

What is it when the normal autonomic or visceral response with an environmental stimulus is replaced with a reflux chosen by the experimenter

Answer 169

Classical or Pavlovian conditioning

also called conditioned reflex

Question 170

What was Pavlov’s experiment?

Answer 170

Conditioned dog to salivate with an arbitrary stimulus (bell) was rung

Question 171

What is pseudoconditioning?

Answer 171

Phenomenon that can be confused with true classical conditioning

Determine if the conditioning process is actually necessary for the production of a response by a previously “neutral” stimulus

In many cases, the “neutral” stimulus is able to elicit response before conditioning, thus not really requiring conditioning

Key to examine natural stimulus prior to conditioning

Question 172

What are operant or instrumental conditioning?

Answer 172

Involves conditioning responses to stimuli with the use of reward or reinforcement

have used those recently to the conditioning of visceral responses, such as changes in heartbeat

Question 173

Explain B. F. Skinner experiment

Answer 173

Operant conditioning and reinforcement

• Well-known experiment - “skinner box”, consists of a cage with a lever or key and a food dispenser
  
  • food pellet delivered whenever the animal pressed the lever = operant response
• Later experiments he varied the type of reinforcement into two categories:
  
  • Positive reinforcement
    
    • Reward = food, light or electrical stimulation of animal brain “pleasure center”
    • Animal was more likely to repeate the desired behavior response
      
      • developed a positive connection between action and reward
  • Negative reinforcement
    
    • links the lack of a certain behavior with a reward
    • Animals developed a negative connection betwen action and reward

Question 174

What is an operant response?

Answer 174

reward when something was done

ie. food delivered when animal presses the lever

Question 175

Explain the punishment behavior

Answer 175

• Punishment:
  
  • conditioning so an organism will stop exhibiting a given behavior pattern
  • painfully shocking organism
  • after, organism is less likely to repeat behavior
    
    • developes a negative connection between stimulus and response

Question 176

Explain Habit family hierarchy

Answer 176

A stimulus is usually associated with several possible responses, each response having a different probability of occurance, stimulus-behavioral association = habit family hierarchy

• ex. A chicken may respond to light in different ways, but one way is rewarded, the rewarded response will occur with a higher probability in the future
  
  • reward strengthens a specific behavioral response and raises its order in the hierarchy

Question 177

What is extinction of conditional behavior

Answer 177

when the reward or reinforcement is gone

Question 178

What is generalization and discrimination of conditional behavior

Answer 178

• Stimulus generalization:
  
  • ability of a conditioned organism to respond to stimuli that are similar, but not identical, to the original conditioned stimulus
• Stimulus discriminiation:
  
  • ability of the learning organism to respond differentlly to slighly different stimuli

Question 179

What is it when environmental patterns or objects presented to a developing organism duringa brief critical period in early life become accepted permanently as an element of its behavioral environment (“stamped in”

Answer 179

Imprinting

ex. swan in a pond with hatched ducklings separated from mother and found that they eventually follow the swan like a mother

Question 180

What are intraspecific interactions

Answer 180

occurs as a means of communication between members of a species

Question 181

Describe behavioral displays of intraspecific interactions

Answer 181

• May be defined as an innate behavior that has evolved as a signal for communication between members of a species
  
  • ex. song, call, or intertional change in an animal’s physical characteristics is considered a display
• Categories of displays:
  
  • Reproductive displays:
    
    • function as signals in preparation of mating
  • Agonistic displays:
    
    • specific actions to communicate
      
      • ex like a dog display of appeasement when it wags it tail
  • Other:
    
    • various dancing procedures by honeybees - location and quality of food
    • auditory, visual, chemical and tactile elements as means of communication

Question 182

Explain the pecking order in intraspecific interactions

Answer 182

• When food, mates or territory are disputed, a dominant member of the species will prevail over a subordinant one
  
  • Social hierarchy = pecking order

Question 183

Explain territoriality intraspecific interactions

Answer 183

• Members of most land-dwelling species defend a limited area or territory from intrusion by other members of the species

Question 184

Explain response to chemicals as an intraspecific interactions

Answer 184

• Olfactory sense is immensely important as a means of communication in many animals
  
  • pheromones
    
    • influence the behavior of other members of the sampe species
• Pheromones can be classified into two types:
  
  • Releaser pheromones
    
    • trigger a reversible behavioral change in the recipient in short-term
      
      • sexual attractant pheromones
      • alarm or toxic defensive
  • Primer pheromones
    
    • long-term behavioral and physiological alterations in receiving animals
      
      • may effect cycles
      • limit sexual reproduction
      • Important in social insects like ants, bees, and termites where they regulate role determination and reproductive capacities

Question 185

What is ecology?

Answer 185

The study of interactions between organisms and their environment

Question 186

What is the difference between abiotic and biotic?

Answer 186

• abiotic = physical or nonliving environtment
  
  • climate, temperature, availability of light and water, and the local topology
• biotic = living environment
  
  • all living things that directly or indirectly influence the life of the organism
    
    • including the relationships that exist between organisms

Question 187

What is the levels of an organisms?

Answer 187

organ system

organ

tissues

cells

molecules

atoms

subatomic particles

Question 188

What is a population

Answer 188

a group of organisms of the same species living together in the same location

ex. lions in grassland, dandelions on a lawn, flies in a barn

Question 189

What is a community?

Answer 189

consists of a population of different plants and animal species interacting with each other in a given environment

Question 190

What is an ecosystem?

Answer 190

an ecological community encompasses the interaction between living biotic communities and the nonliving environment

Question 191

What are the five kingdoms?

Answer 191

monera

protists

plants

fungi

animals

Question 192

What is a biosphere

Answer 192

includes all protions of the planet that support life:

atmosphere

lithosphere (rocks and soil surface)

hydrosphere (ocean)

Question 193

What is the photic zone?

Answer 193

top layer of the water through which light can penetrate, is where aquatic photosynthetic activity takes place

Question 194

What is the aphotic zone?

Answer 194

only animal life and other heterotrophic life exists

Question 195

What is terrestrial life?

Answer 195

• live predominantly or entirely on land
  
  • oxygen approximately 20%

Question 196

What is the substrantum?

Answer 196

soil and rock

Question 197

What is the substrantum affected by?

Answer 197

• substratum (soil and rocks): determines the nature of plant and animal life in the soil:
• Soil is affected by a number of factors:
  
  • Soil acidity, pH
    
    • Rhododendrones and pins = acidic
    • acid rain may make soid pH too low for most plants growth
  • Texture
    
    • its clay content determines how much water-holding capacity
    • Willows require moist soil
    • Most plants grow will in loams, high percentages of each type of soil
  • Minerals
    
    • including nitrates and phosphates affect type of vegitation that can be supported
    • Beach sand has no minerals, no plant growth
  • Humus quantitiy
    
    • determined by the amount of decaying plants and animal life in the soil

Question 198

What is a niche?

Answer 198

functional role of an organism in its ecosystem

• Describes what the organism eats, where and how it obtains its food, what climactic factors it can tolerate and which are optimal, the nature of its parasites and predators, where and how it reproduces, etc
• Two species cannot occupy the same nitch in the same location
  
  • if same niche results:
    
    • extinction
    • occupy two different location and both go extinct separately
    • diver due to evolution

Question 199

What are autotrophs

Answer 199

organisms that manufacture their own food

• Examples:
  
  • green plants (from sun light)
  • chemosynthetic bacteria (oxidation of inorganic sulfure, iron, nitrogen compounds)

Question 200

What are heterotrophs? what are the types?

Answer 200

cannot synthesize their own food and must depend upon autotrophs and other heterotrophs in the ecosystem to obtain food and energy

• Types:
  
  • Herbivores:
    
    • consume only plants or plant food
      
      • have symbiotic bacteria that can digest cellulos to help them breakdown and utilize cellulose
    • often prey
      
      • cows, horses, hoofs instead of towes
  • Carnivores:
    
    • animals that eat only other animals
  • Omnivores:
    
    • eat both plants and animals

Question 201

What are the major types of interspecific interactions? name and describe

Answer 201

• Symbiosis
  
  • obligatory relationship, cannot survive without the other
  • Types of symbiotic relationships: Commensalism (+/0), Mutualism (+/+), Parasitism (+/-)
• Predation
  
  • free-living organisms that feed on other living organisms
    
    • Carnivors and herbivores
• Saprophytism
  
  • include those protists and fungi that decomposed (digest) dead organism matter externally and absorb the nutrients
    
    • ex. mold, mushrooms, bacteria of decay, and slime molds
• Scavenging
  
  • animals that consume dead animals
    
    • ex. vulture, hyena, snapping turtle

Question 202

What is symbiosis and its relationships

Answer 202

• Symbiosis
  
  • may or may not be beneficial to both participants
  • obligatory relationship, cannot survive without the other
  • Types of symbiotic relationships:
    
    • Commensalism (+/0)
      
      • ​host neither discourages nor fosters the relationship
    • Mutualism (+/+)
    • Parasitism (+/-)

Question 203

Explain osmoregulation with organisms and their environment

Answer 203

• animals adaptation for maintaining their internal osmolarity and conserving water

Question 204

What is poikilothermic?

Answer 204

animals and plants that are cold-blooded

Question 205

What is homeothermic?

Answer 205

warm-blooded

Question 206

explain in detail the levels of the food chain, with examples

Answer 206

1. Producers:
   
   • The autotrophic green plants and chemosynthetic bacteria
   • utilize energy from the sun and simple raw materials to manufacture carbohydrates, proteins and lipids
   • ex. wheat plant
2. Primary Consumers:
   
   • animals that consume green plants (herbivores)
   • ex. cows, grasshoppers and elephant
3. Secondary Consumers:
   
   • animals that consume primary consumers (carnivores)
   • ex. frogs, tigers, dragonflies
4. Tertiary Consumers:
   
   • animals that feed on secondary consumers (carnivores)
5. Decomposers:
   
   • saprophytic organisms and organisms of decay, bacteria and fungi, as they decompose the organic wastes and dead tissues into simpler compounds, nitrates and phosphate

Question 207

What changes elemental nitrogen (N2) into usable form?

Answer 207

lightning and nitrogen-fixing bacteria in the roots of legumes change nitrogen to usable, soluble nitrates

Question 208

What happens to the nitrates by plants in the nitrogen cycle?

Answer 208

nitrates are absorbed by plants and are used to synthesize nucleic acids and plant proteins

Question 209

What happens when the animals eat the plans in the nitrogen cycle?

Answer 209

Animals eat the plansts and synthesize specific animal proteins from the plant proteins

Question 210

What happens when the animal poops in the nitrogen cycle?

Answer 210

Nitrogen locked up in waste and dead tissues is released by the action of bacteria of decay, which converts the proteins into ammonia (NH3)

Question 211

What happens with ammonia from the poop in the nitrogen cycle?

Answer 211

• two fates await the ammonia:
  
  • some nitrified to nitrites by chemosynthetic bacteria and then to usable nitrates by nitrifying bacteria
  • The rest is denitrified
    
    • ammonia is broken down to release free nitrogen, returning to beginning of cycle

Question 212

What are the four kinds of bacteria that are involved in the nitrogen cycle?

Answer 212

1. Decay
2. Nitrifying
3. Denitrifying
4. Nitrogen fixation

They have no use for the excretory ammonia, nitrates, nitrates and nitrogen they produce; however, they do impact other living organisms

Question 213

What are the terrestria biomes?

Answer 213

• Desert biome
• grassland biome
• rainforest biome
• Temperate deciduous forest biome
• Temperate coniferous forest biome
• Taiga biome
• Tundra biome
• Polar region

Question 214

Explain the Desert biome

Answer 214

• receive fewer than 10 inches of rain/year
• rain is concentrated within a few heavy cloudbursts
• growth season = few days after rainfall
  
  • generally small plants and animals
    
    • plants conserve water: cactus, sagebrush and mesquite
    • animals live in burrows (insects and lizards)
• Examples: Sahara in africa and Gobi in Asia

Question 215

Explain the Grassland biome

Answer 215

• Characterized by low rainfall (10-30 inches/year)
• provide no shelter for herbivorous mammals (bison, antelope, cattle, and zebra) from predators
  
  • have long legs and hoofed
• ex. prairies east of the Rockies, steppes of Ukrain and pampas of Argentina

Question 216

Explain the Rainforest biome

Answer 216

• aka jungles, characterized by torrentrial rains
• tropical rainforests = high temperatures
• temperature rainforests = moderate temperature
  
  • both include climax communities with dense growth of vegetation
    
    • ex. vines and epiphytes (plants grwoing on other plants)
    • ex. monkeys, lizards, snakes, and birds
  • Floor is inhabited by saprophytes, live off dead organic matter
• Tropical = central africa, central america, amazon basin and southeast asia
• temperate = western north and south america and islands off eastern asian and australian coasts

Question 217

Explain the Temperate deciduous forest biome

Answer 217

• cold winters, warm summers, and moderate rainfall
• beech, maple, oaks, and willow trees which shed their leaves during cold winter months
• animals - deer, foxes, woodchucks, squirrels, and birds
• found in northeastern and central-eastern US and Central Europe

Question 218

Explain Temperate coniferous forest biome

Answer 218

• Forests are cold, dry and inhabited mainly by trees that do not lose their leaves
  
  • such as fir, pine and spruce trees
    
    • adapted for water conservation
      
      • needle shaped leaves
• Found in extreme northern parts of US and southern Canada
  
  • largest biomass of any terrestrial biome
    
    • trees like redwood
    • animals like beavers, bears, sheep, squirrels and birds

Question 219

Explain the Taiga biome

Answer 219

• Receive less rainfall than temperate forest
• long, cold winters and like coniferous forests, are inhabited by trees that do not lose their leaves, especially spruce
• Soils: thin soil covered in moss and lichens
• animal: moose and deer, bears, wolves, rodents and birds
• Exist in extreme northern parts of Canada and Russia

Question 220

Explain the Tundra Biome

Answer 220

• Treeless, frozen plain found between the taiga and the northern ice sheets
• covered in snow and ice for much of the year and can be described as permafrost
• lichens, mosses, polar bears, musk oxen and arctic hares are found here

Question 221

Explain the polar region

Answer 221

• surround the polar ice caps and are frozen areas with no vegetation and few terrestrial animals
• include penguins and polar bears
• little precipitation falls therefore deserts

Question 222

There are two types of aquatic biomes, marine and freshwater.

Explain the marine biome

Answer 222

• Oceans connect to form one continuous body of water, controling earth’s temperature by absorbing solar heat
• Distinct zones of the marine biome:
  
  • Intertidal zone:
    
    • Region exposed at low tides, variations in temperature and dryness
    • algae, sponges, clams, snails, sea urchins, starfish and crabs
  • Neritic zone:
    
    • On the continetal shelf that contains ocean with depths up to 600 ft and extends several hundred miles from the shore
    • algae, crabs, crustaceans and many species of fish
  • Pelagic zone:
    
    • typical of the open sea, divided into photic and aphotic zone
  • Photic zone:
    
    • sunlit layer of open sea extending to depth of 250-600ft
    • plankton (photosynthetic and hterotropic organisms), nekton (active swimmers like fish, sharks or whales that feed on plankton and smaller fish)
    • Chief autotroph is the diatom, an alga
  • Aphotic zone:
    
    • region beneath the photic zone that receives no sunlight
    • only heterotrophs
      
      • very cold, high pressure env.
    • contains nekton and benthos (crawling and sessile organisms)

Question 223

There are two types of aquatic biomes, marine and freshwater.

Explain how freshwater differs from marine biome

Answer 223

• Freshwater is hypotonic, creating a diffusion gradient that results in the passage of water into the cells
  
  • freshwater organisms have homeostatic mechanisms to maintain water balance by regular removal of excess water
    
    • contractile vacuoles of protozoa and excretory systems of fish
    • plants have rigid cell walls thus build up cell pressure (turgor) as water flows in
      
      • pressure stops the influs
• In rivers and streams, strong, swift currents exist, and thus selection favored the survival of fish that developed strong muscles and plants with root-like holdfasts
• Freshwater biomes, except very large lakes, are affected by variations in climate and water
  
  • temperature of freshwater bodies may very considerably, freeze or dry up, and mud from those floors may be stirred up by the storms

Question 224

What is the major taxonomy divisions, top down

Answer 224

1. Domain
   
   • Eukarya
2. kingdom
   
   • Animalia
3. phyla (or divisions)
   
   • Chordata
4. class
   
   • Mammalia
5. order
   
   • Primates
6. family
   
   • Hominidae
7. genus
   
   • Homo
8. species
   
   • Sapiens

Question 225

What makes up the Monera Taxonomy group? explain

Answer 225

• Lack a nucleus or any membrane-bound organelles and are single-celled organisms that reproduce asexually
• Eubacteria
  
  • single celled prokaryotes with a single double-stranded ciruclar loop of DNA not enclosed by a nuclear membrane
    
    • Morphological, cocci (round), bacilli (rods), spirilla (spiral),duplexes (diplo-), clusters (staph-), chains (strepto-)
  • Cyanobacteria
    
    • types of bacteria that live primarily in fresh water but also exist in marine environments
    • Posses a cell wall and photosynthetic pigments
• Archaea
  
  • prokaryotes, and often have cell walls and flagella, also exhibit several unique variations
    
    • cell membrane composed of glycerol-ether lipids = extreme environments

Question 226

What are the types of Protists, name and briefly describe

Answer 226

• primative eukaryotic organisms with membrane-bound nuclei and organelles
• capability to carry out all of the life processes
• Types:
  
  • Protozoa
    
    • single-celled organisms that are heterotrophic
    • Categories:
      
      • Rhizopods = amoebas, pseudopods
      • ciliophors = cilia use for feeding and locomotion
  • Algae
    
    • Primarily photosynthetic organisms
      
      • all colors but blue-green (cyanobacteria)
    • Ex. phytoplankton and kelp
  • Slime Molds
    
    • formerly placed in fungi, now considered protists
    • are arranged in a coenocytic (many nuclei) mass of protoplasm
    • life cycle = animal like and plant like stages
    • Produce asexually by sporulation

Question 227

Describe Fungi

Answer 227

• Considered nonphotosynthetic plants (ie. they resemble plants in that they are eukaryotic, multicellular, differentiated and nonmotile)
  
  • have cell walls composed of chitin and not cellulose, used by plants
• Eukaryotes and primarily multicellular
  
  • heterotrophs
• May be: saprophytic (decomposing dead organic material) or parasitic (extracting nutrients from hosts)
• Reproduces asexually by sporulation or intricate sexual processes
• Mushrooms, yeast, and lichens

Question 228

Explain Plantae taxonomy

Answer 228

• nonmotile photosynthetic
  
  • make own energy = autotrophs
• tissue layers contain chloroplasts for manufacturing carbs.
• absorption tissues, like roots and simpler rhizoids
• conducting or vascular tissue transport water, minerals and nutrients to plant
• waxy surround = cuticles
• Cells are in direct contact with the external environment by means of air spaces called stomata
• Divisions = bryophytes and tracheophytes

Question 229

Explain the Bryophytes division of the Plantae Taxonomy

Answer 229

• Bryophyta, hepatophyta and anthocerotophyta divisions (informally called bryophytes) are simple plants with few specialized organs and tissues
  
  • lack the water-conducting woody material (xylem) that support in tracheophytes
• These type of plants undergo alternation of generations
  
  • gametophyte = dominante generation
    
    • the “main” plant and is larger and nutritionally independant
  • Sporophyte
    
    • smaller and shorter lived,growing off the gametophyte from the archegonium
      
      • heterotroph parasite
• Mosses are classic bryophytes - sporophytes and gametophytes generations grow together
• Liverworts are flat, horizontal and leaf-like plants with differentiated dorsal and ventral surfaces

Question 230

Explain the Tracheophytes division of Plantae

Answer 230

• Vascular plants (tracheophytes) are complex plants with a great degree of cell differentiation
  
  • contain vascular tissues: Xylem (water-conduction) and phloem (food-conduction)
• Composed of:
  
  • Non-seed-bearing
    
    • Pterophytes (ferns)
    • Lycophytes (club mosses)
  • Angiosperms
    
    • Angiosperms
    • Dicotyledons (dicots)
    • Monocotyledons (monocots)
  • Gymnosperms
    
    • Gymnosperms (naked-seeding plants)
    • Conifers (pines, spruce and firs)

Question 231

Explain the non-seed-bearing Tracheophytes

Answer 231

• Two extant divisions of non-seed-bearing vascular plants:
  
  • Pterophytes:
    
    • familiar fern
    • grown from an underground stem = rhizome, and contain large leaves (megaphylls)
    • Ferns grow lengthwise, not in diameter, and contain xylem with elongated tracheid cells that transport salt and water
  • Lycophytes:
    
    • have roots, are nonwoody and contain microphylle leaves

Question 232

Explain the Angiosperm Tracheophyte Plantae taxonomy group

Answer 232

• Angiosperms:
  
  • contain the greatest number of different plant species
  • have covered seeds and are most abundant of all plants
  • have flowers, not cones as their reproductive structure
    
    • another of male stamen produces microspores (pollen grains) while the ovary of the female pistil produces megaspores
• Dicotyledons (dicots)
  
  • angiosperms with net-veined leaves and vascular bundles around a ring within the central cylinder
  • contain two cotyledons (seed leaves)
  • have cambius and can be woody
  • flower parts in 4 to 5 multiples
  • ex: maple, apple trees, potatoes, carrots, goldenrods, buttercups
• Monocotyldons (monocots)
  
  • angiosperms that contain leaves with parallel veins, scattered vascular bundles, seeds with single cotyledons (single leave)
  • most do not have cambium and nonwoody (herbaceous)
  • Flower parts in multiples of three
  • ex. grasses (wheat, corn, rye, and rice), sugar cane, pinapple, irises, bananas, orchids, and palms (woody monocots)

Question 233

What are Gymnosperms area of Tracheophytes in the Plantae Taxonomy group

Answer 233

• Are naked-seeded plants
• gymnosperms is short-lived and microscopic
• Male microspores produces pollens, carried by wind
  
  • requirement of a water env.
• Presence of a specialized cambium tissue allows for secondary growth of secondary xylem (wood) and secondary phloem
  
  • grow in diameter as well as length and woody
    
    • not herbaceous (green with soft stems)
• Most are evergreens (non-deciduous)
• Divisions:
  
  • conifers
    
    • largest group of gymnosperms
      
      • pines, spruces, and firs
  • Cycadophyta (cycads)
    
    • stout, cylindrical trees with pinnate (feather-like) leaves
  • Gnetophyta (gnetophytes)
    
    • widely varying properties but tend to be vine like
  • Ginkgophyta (ginkgo)
    
    • only has one extant species, Ginkgo tree, grows pungent seens and sometimes used in herbal medicines

Question 234

Explain the Animalia kingdom

Answer 234

• Multicellular, generally motile, heterotrophic organisms that have differentiated tissues
• with exception of some parasites like the tapeworm, animals ingest bulk food, digest them and eliminate remains
• usually require movement for nutrients, but some are sessile (stationary) and create currents to trap food
• Simple multicellular:
  
  • sponges, coelenterates, flatworms, minimal differentiation
    
    • direct contact with outside env.
    • few systems: digestive and reproductive
• Advanced animals: specialized tissues and systems
• Most have a right and left sides that mirror image one another = bilateral symmetry
• Some such as echinoderms and cnidarians have radial symmetry

Question 235

What are some examples of Phyla in the Animalia kingdom

Proifera

Cnidaria

Platyhelminthes

Nematada

Annelida

Mollusca

Arthropoda

Echinodermata

Chordata

Vertebrata

Answer 235

• Porifera: contains sea sponges, have two layers of cells, pores, and low degree of cellular specialization.
  
  • usually sessile (cannot move for food)
• Cnidaria: contain a digestive sac that sealed at one end. Two layers of cells are present, extoderm and endoderm
  
  • specialized featers: tentacles, stinging cells and nerve nets (ex. hydra, jellyfish, anemones, and coral)
• Platyhelminthes: flatworms with ribbon-like, bilaterally symmetrical bodies. Three germ layers
  
  • do not have circulatory systems, and nervous systems consist of eyes and anterior brain ganglion and pair of longitudinal nerve cords
• Nematoda: Roundworms, long digestive tubes and anuses. Solid mesoderm.
  
  • lack circulatory system, possess nerve cords and anterior nerve rings (ex. hookworms, trichina, and free-living soil nematodes)
• Annelida: segmented worms that possess a coelom (true body cavity) in mesoderm. Have well-defined systems, nervous, circulatory and excretory systems
  
  • ex. earthworms and leeches
• Mollusca: soft-bodied and possess mantels that often secrete calcareous (calcium carbonate) exoskeletons
  
  • breathe by gills and contain chambered hearts, blood sinuses, ventral nerve cords (ex. clams, snails, squid)
• Arthropoda: jointed appendages, chitinous exoskeletons, open circulatory systems (sinuses)
  
  • Classes:
    
    • insects: spiracles and tracheal tubes for breathing, have three pairs of legs
    • arachnides: four pairs of legs and book lungs (scorpions and spiders)
    • crustaceans: segmented bodies veriable appendage numbers, also have gills (ex.lobsters, crayfish and shrimp)
• Echinodermata: spiny, radially symmetrical, water-vascular system, capacity for regeneration parts
  
  • link between echinoderms and chordates. (ex. starfish and sea urchin)
• Chordata: stiff dorsal rod, notochord, during development. Paired gills slits and tail extending beyond anus.
  
  • Lancelets and tunicates (amphioxus) are chordates) - no backbone
• Vertebrates: include amphibians, reptiles, birds, fish, and mammals
  
  • possess bones, vertebrae, forming the backbone. replace notochords of the embryo and protect nerve cord

Question 236

What are the classes of vertebrates in the Animalia phylum of the Taxonomy system

Agnatha

Chondrichthyes

Osteichthyes

Amphibia

Reptialia

Aves

Mammalia

Answer 236

• Agnatha: jawless fish, instead have a suckling mouth (ex. lamprey and hagfish)
• Chondrichthyes: Cartilaginous fish possess jaws and teeth (ex. sharks)
• Osteichthyes: bony fish and most prevalent. have scales and lack notochord in the adult form. cartilage is replaced by bony skeleton (ex. sturgeon, trout and tuna)
• Amphibia: larval stages found in water but adult stages live on land. Possess gills and a tail with no legs, adults have lungs, two pairs of legs, no tail and three chambered heart and no scales (frogs, salamander, toad and newt)
• Reptialia: live on land, breathe air by lungs, lay leathery eggs, and utilize internal fertilization. cold-blooded (poikilothermic) have scales and three-chambered heart (ex. turtle, lizard, snake and crocodile
• Aves: birds, four chambered heart. warm blooded (homeothermic) eggs are surrounded by shell (ex. hen and eagle)
• Mammalia: warm-blooded and feed their offspring with milk.
  
  • monotremata order lay leathery eggs, horny bills and produce milk but no nipples (ex. duck-billed platypus and spiny anteater)
  • Marsupials: infraclass of pouched mammals (kangaroo and opossum)
  • Placentalia: embryos that develop fully in the uterus (humans, bats, whale, mouse)

Question 237

Explain Viruses

Answer 237

• do not carry out physiological or biochemical processes outside of a host
• may be considered nonliving
• Viruses have lytic and lysogenic life cycles
• They contain either DNA or RNA and some essential enzymes surrounded by a protein coat
• Exclusively infect bacteria - bacteriophages

Question 238

Name and describe the two main layers of skin

Answer 238

• Dermis
  
  • Blood supply and specialized cells
• Epidermis
  
  • Keratinocytes
    
    • differentiate into protective, waterproof cells called corneocytes

Question 239

Where is the antigen-binding region found on the immunogloulin structure?

Answer 239

N-terminus

Question 240

What is the role of histomine in the immune response?

Answer 240

To dilate the blood vessels

Question 241

What are nonself cells remembered as?

Answer 241

antigens

Question 242

What are two major types of immunity

Answer 242

• Humeral
  
  • antibody production
• Cell-mediated
  
  • cells that combat fungal and viral infections

Question 243

What occurs during inflammatory response

Answer 243

• Nonspecific defense mechanism
• White blood cells are activated they release chemical, such as histamine, that activate the immune response by:
  
  • dialating and increasing permeability of blood vessels
  • Often accompanied by an increase in body temperature, fever

Question 244

Explain the lymphatic system, what are the reserviors?

Answer 244

• Found in extravascular space of most tissue
• Lymph node and spleen serve as a reservoirs of white blood cells and filter for lymph
  
  • removing antigen-presenting cells and foreign matter and activating the immune system when necessary

Question 245

Explain cell mediated immunity, what are the two types?

Answer 245

• Innate immunity = rapid response
  
  • Body’s initial, generalized defense
  • does not require cells that are aquired from previous infections
  • not a specific response
    
    • anatomical features (skin)
    • physiological response (fever, pH change, enzymes)
    • phagocytic cells (monocytes, neutrophils, macrophages)
    • Inflammation
• Adaptive Immunity = slow response
  
  • Acquired or specific = cells that recognize self versus nonself cells
  • Contain memory components aquired through previous exposure
    
    • Lymphocytes (B and T cells)
    • Plasma cells
    • Antigen-presenting cells (macrophages, B cells)

Question 246

Explain Granulocytes and the types

Answer 246

• Attracted to site of injury, where they phagocytize antigens and antigenic material
• Neutrophils:
  
  • Most common and first responders
  • Attracted to cytokines and in tern attract additional WBC’s once they arrive
  • Mainly adapted to attack bacteria
  • Elevated during acute stage of inflammation and are main component of pus
• Eosinophils:
  
  • less common
  • Allergic and asthmatic response or presence of endoparasites, live on skin, such as helminth (type of parasitic worm)
• Basophils (mast cells)
  
  • Least common
  • Allergic response and often are responsible for the release of histaminc, stimulate blood vessel dialation
  • Also for ectoparasite, live on surface of skin, fleas and ticks

Question 247

Explain Monocytes

Answer 247

• Are large, long-lived immune cells that can differentiate into macrophages and dendritic cells
• Macrophages
  
  • Phagocytize dead cells and pathogens
  • If pathogen is ingested, its antigens are then presented on the surface of macrophage to stimulate other immune response, mount a specific invading pathogen
• Dendritic Cells
  
  • Focused on precessing antigens and presenting them to other immune cells
    
    • important link between innate and adaptive immune system
  • Found in areas of body in contact with external env. (skin, intestine, mucous mem.)

Question 248

What are the two Lymphocytes

Answer 248

T Lymphocytes

B Lymphocytes

Question 249

What is the T Lymphocytes responsible for?

Answer 249

• Specific immunity, reactivate to one specific antigen
• If infection with the previous infection, antigen present, the antigen form the pathogen will be presented by a major histocompatibility protein complex (MHC) on the surface of the antigen-presenting cell, indecating T cell should perform its function
• Vast majority of T cells are destroyed, dont react to MHC or react too much (apoptosis)
• Two major MHC: MHC I and MHC II

Question 250

Explain the major types of T Lymphocytes and what MHC they belong to

Answer 250

• Cytotoxin T (Tc) cells (CD8+T cells)
  
  • Contain 8 proteins (CD)
  • Recognize and respond to antigens presented by MHC I complex
  • Come from cells impacted by viruses or developing tumors and signal Tc to destroy cells
• T helper (T_H) cells (CD4+ T cells):
  
  • 4 CD protein
  • Recognize and respond to antigens presented by MHC II complexes
  • Activated T_H cells release cytokines to stimulate the immune response, causing other white blood cells to mature and attack
• Natural Killer T (NKT) cells
  
  • Behave similarly to Tc and T_H cells but respond to antigens presented by other types of cells

Question 251

What is the function of Regulatory or suppressor T (Treg) cells?

Answer 251

Serve to tone down T cell response to self cells or following an infection

Question 252

Where do T cells develop vs. B cells?

Answer 252

• T cells:
  
  • Begin in bone marrow, where precursor cells form
  • Travel to the thymus where they mature
• B cells:
  
  • Begin and end development in Bone Marrow

Question 253

Explain B lymphocytes

Answer 253

• When stimulated, they create and express antibodies (immunoglobulins) that have a high affinity for the antigen expressed by the stimulating T lymphocytes
  
  • Immunoglobulin have a very particular structure and utilize the specificity of this structure to aid in the targeted destruction of pathogens
  • Like T cells, B cells an also stimulate the formation of memory cells
    *

Question 254

What is Humoral Immunity?

Answer 254

Not cells,

various chemicals, hormones, and enzyme supplement the action of the cells and serve equally important roles

Question 255

Explain the structure and function of Antibodies

Answer 255

• Large proteins secreted by B cells known as antibodies (immunoglobulins) provide specific, targeted response to a given antigen
• Exist in the form of a Y
  
  • antigen binding sites at the N-terminus end (two ends of the Y)
  • Each side of structure consists of two chains (light and heavy chain held by disulfide bonds)
  • Variable portions of the structure is the antigen-binding region (inside the Y)

Question 256

What does the Antibody-mediated immunity consist of

Answer 256

• Active Immunity:
  
  • As a result of an immune response to an exposure of a pathogen or antigen, like infection
  • Could also be from a vaccine that stores “nonself” memory
• Passive Immunity:
  
  • Transfer of antibodies from one individual to another:
    
    • Pregnancy
    • Or injection of gamma globulin, fractions of the blood containing antibodies
  • Effective immediately, but once no longer circulating, the immunity is lost

Question 257

What are neuroglia

Answer 257

cells that support and protect the neurons

Question 258

Name and describe the fuction of the cells in the Central Nervous System

Answer 258

• Astrocytes:
  
  • Maintain the integrity of the blood-brain barrier, absorbe nutrients and dissolved gas and absorb and recycle neurotransmitters
• Oligodendrocytes:
  
  • Myelinate CNS axons as well as provide structural framework for the CNS
• Microglia:
  
  • Remove cellular debris and pathogens
• Ependymal Cells:
  
  • Line and brain ventricles and aid in the production, circulation and monitoring of cerebral spinal fluid

Question 259

Name and describe the function of the cells in the peripheral nervous system

Answer 259

• Satellite cells:
  
  • Surround the neuron cell bodies in the ganglia
• Schwann cells:
  
  • Enclose the axons in the PNS and aid in the myelination of some peripheral axons

Question 260

Explain the action potential propagation of an excited nerve, what happens during the excited state/stages to get there?

Answer 260

see attached

Question 261

Explain some of the drug effects on the neurons

Answer 261

• Curare:
  
  • Blocks postsynaptic nicotinic acetylcholine receptors, such as those on muscles, so acetylcholine is unable to interact with them. This leads to muscle relaxation and paralysis by blocking the ability to constrict muscles
• Botulinum toxin:
  
  • Prevents the release of acetylcholine from the presynaptic membrane and also results in paralysis
• Anticholinesterases:
  
  • Used as nerve gases and in the insecticide parathion. These inhibit the activity of the acetylcholinesterase enzyme responsible for degrading acetylcholine released int he synapse. Results is acetylcholine not degraded and continues to affect the post synaptic membrane. Therefore, no coordinated muscular contractions can take place

Question 262

What are the main divisions of the brain?

Answer 262

Forebrain

Midbrain

Hindbrain

Question 263

What is in the Forebrain and what is another name for it?

Answer 263

• Forebrain = Prosencephalon
• Consists of the Telecephalon and Diencephalon
  
  • Telecephalon:
    
    • Cerebral cortex ​
      
      • gray matter on surface
      • Sensory and motor responses
        
        • olfactory bulb - smell
  • Diencephalon:
    
    • Thalamus
      
      • relay and integration center for the spinal cord and cerebral cortex
    • Hypothalamus
      
      • controls visceral function
        
        • hunger, thirst, sex trive, water balance, blood pressure and temperature
        • endocrine system control

Question 264

What is in the Midbrain and what is the alternate name?

Answer 264

• Midbrain = Mesencephalon
• Relay center for visual and auditory impulses and motor control
• tectum and tegmentum

Question 265

What is in the Hindbrain and what is the alternate name?

Answer 265

• Hindbrain = Rhombencephalon
  
  • aka brain stem (midbrain, pons, medulla)
• Posterior part of the brain that consists of the cerebellum, pons and medulla
  
  • Cerebellum:
    
    • Modulate motor impulses initiated by the cerebral ortex
    • important for maintenance of balance, hand-eye coordination, and the timing of rapid movement
  • Pons:
    
    • acts as a relay center to allow the cortex to communicate with the cerebellum
  • Medulla
    
    • Controls vital function: breating , heart rate, and gastrointestinal activity

Question 266

By increasing the intensity of the stimulus, the action potential will?

Answer 266

increase in frequency

Question 267

When a muscle is subjected to very frequent stimuli what happens?

Answer 267

a simple twitch is repeatedly generated

Question 268

Which type of muscle is always multinucleated?

Answer 268

Skeletal

Question 269

Which type of muscle(s) has strong, forceful contractions?

Answer 269

Cardiac and skeletal muscles

Question 270

Which type of muscle lacks sacomeric striations?

Answer 270

smooth muscle

Question 271

Explain the difference between the types of muscles

Answer 271

see attached