Ch 42 Flashcards
Diffusion Traits (2)
1) Efficient over small distances
2) Time to diffuse proportional to the square of distance
How do most animals exchange materials with the environment?
Via a fluid-filled circulatory system
Some cnidarians have elaborate gastrovascular cavities that function in both
Digestion and Distribution
How thick is the body wall that encloses the gastrovascular cavity?
Two cells thick
What does a circulatory system have (3)
1) Circulatory fluid
2) Set of interconnecting vessels
3) Muscular pump, the heart
What does the circulatory system do?
Connects fluid that surround cells with organs that exchange gas, absorb nutrients, and dispose of wastes
How does an open organ circulatory system work?
Circulatory fluid called HEMOLYMPH bathes organs directly
What is a closed circulatory system?
Blood is confined to vessels and is distinct from the interstitial fluid
(annelids, cephalopods, and vertebrates)
What closed circulatory system do humans have?
Cardiovascular system
Three main types of blood vessels (3)
1) Arteries
2) Capillaries
3) Veins
(Blood flows from 1-3 and is one way)
Organization of circulatory systems
Arteries, arterioles, capillaries, venules, vein
(ateries, arterioles, capillaries - away from heart; venules, veins - to
What are capillary beds?
Sites of chemical exchange between blood and interstitial fluid
How are arteries and veins distinguished?
Direction of blood flow, not O2 content
How many chambers do vertebrate hearts have?
two or more
Where does blood enter and then leave in a heart?
Blood enters through an Atria and pumped out through Ventricles
What type of circulation do bony fishes, rays, and sharks have?
Single circulation and two-chambered heart
What is single circulation?
Blood leaves the heart passes through two capillary beds before returning
What is double Circulation?
(Mammals, reptiles, and Amphibians)
Oxygen poor and oxygen rich blood are pumped separately from the right and left sides of the heart
Reptiles and Mammals use what type of circuit?
Pulmonary circuit which picks up oxygen from the lungs
Amphibians use what type of circuit?
Pulmocutaneous circuit to pick up oxygen from lungs and skin
What is systemic circuit?
When Oxygen rich blood delivers oxygen
Difference between double circulation and single circulation?
Higher blood pressure in organs for double circulation
What kind of heart do frogs have?
Three chambered with ridge:
Two atria and one ventricle
Describe the Amphibian heart system?
Ridge in ventricle diverts oxygen rich blood to SYSTEMIC circuit and poor oxygen blood into PULMOCUTANEOUS circuit
What kind of heart do turtles, snakes, and lizards have?
3 chambered heart: 2 atria 1 ventricle
Partially divided by incomplete septum
What kind of hearts do Alligators, Caimans, and crocodiles have?
Have a septum that divides the ventricles, but pulmonary and systemic circuits connect where arteries exit the heart
What kind of hearts do mammals and birds have?
Four chambered heart
Two atria and two ventricles
Describe the heart of mammals and birds?
Left side of heart pumps and receive ONLY oxygen rich blood
Right side receives and pumps ONLY oxygen poor blood
Traits of atria
Relatively thin walls and serve as collection chambers for blood returning to the heart
Traits of ventricles
Have thicker walls and contract more forcefully
What is cardiac cycle?
The heart contracts and relaxes in a rhythmic cycle
Contraction or pumping
Systole
Relaxation or filling
Diastole
What is cardiac output?
Volume of blood pumped into the systemic circulation per minute
Depends on both heart rate and stroke volume
What is heart rate?
beats per minute
What is stroke volume?
Amount of blood pumped in single contraction
What valve separates each atrium and ventricle
Atrioventricular Valves
tricuspid and bicuspid (mitral) valve
What valves control blood flow to the aorta and pulmonary artery?
Semilunar valves
Aortic semilunar valve and Pulmonary semilunar valve
What creates the lub-dup sound of a heart?
Recoil of blood against the atrioventricular valves (lub) then against the semilunar (dup) valves
What is heart murmur
Backflow of blood through a defective valve causes heart murmur
How is cardiac muscle autorhythmic?
Some cardiac muscle contract without any signal from the nervous system
What is the Sinoatrial node?
Sets the rate and timing at which cardiac muscle cells contract
What are impulses that travel during the cardiac cycle can be recorded as an
Electrocradiogram
What is the pacemaker regulated by?
Sympathetic (speed up)
Parasympathetic (slow down)
Hormones
temperature
What is endothelium?
Central lumen lined with epithelial layer
Lines blood vessels
Characteristics of capillaries
Slightly wider than a red blood cell
Thin walls for exchanging materials
What are the walls of capillaries made of?
Endothelium
Basal lamina
Characteristics of Arteries
Thick elastic walls for high blood pressure
Characteristics of Veins
Thinner walls
Contains valves to maintain unidirectional flow
Describe the velocity of blood flow in capillaries
Slow because of high resistance and large cross-sectional area
Allows exchange of material
Explain blood flow regarding pressure
Flows from high pressure to low pressure
Maintained by recoil of elastic arterial walls
What is systolic pressure?
Pressure in arteries during ventricular systole
What is diastolic pressure?
Pressure in arteries during diastole
What is pulse
Rhythmic bulging of artery walls
What is vasoconstriction
Contraction of smooth muscles in arteriole walls
Increased blood pressure
What is vasodilation
Relaxation of smooth muscles in arteriole walls
Decreased blood pressure
What is a major inducer of vasodilation?
Nitric Oxide
What induces vasoconstriction?
Endothelin
What natural force plays a role in blood pressure?
Gravity
What is healthy blood pressure for 20 year old?
120 mm hg at systole
80 mm hg at diastole
What causes fainting?
Inadequate blood flow
How is the return of blood enhanced
Contraction of smooth and skeletal muscles
Traits of capillaries in major organs?
Filled to capacity
(blood supply varies at other sites)
Two mechanism that regulate distribution of blood in capillary beds?
1) Constriction or dilation of arterioles that supply capillary beds
2) Precapillary sphincters that control flow of blood between arterioles and venules
What is blood flow regulated by
Nerve impluses, hormones, and chemicals
______ tends to drive fluid out of capillaries
Blood pressure
_____ tend to pull fluid back
Blood proteins
(responsible for much of the bloods osmotic pressure)
What is the lymphatic system role in blood
Returns excess fluid that leaks from capillary beds back to circulatory system
What is a lymph
Fluid lost by capillaries
Where does lymphatic system drain into
veins in the neck
What is Edema
Swelling caused by disruption in the flow of lymph
What are lymph Nodes
Organs that filter lymph and play a role in body’s defense
(will become swollen when fighting infection)
What is plasma
Liquid matrix where connective tissues are suspended in
What occupies 45% of the volume of blood
Cells and cell fragments
What is plasma made of
inorganic salts dissolved as ions (electrolytes)
What do plasma proteins do? (5)
1) Influence blood pH
2) maintain osmotic balance between blood and interstitial fluid
3) lipid transport
4) immunity
5) blood clotting
Difference between plasma and interstitial fluid
Plasma has higher protein concentration
Red blood cells
Erythrocytes (O2 carriers)
White blood cells
Leukocytes (defense)
What are Platelets?
Fragments of cells that help with clotting
Eryth
red
Leuk
white
Erythrocytes (2)
1) Most numerous blood cell
2) Lack nuclei and mitochondria
What do erythrocytes contain that helps with oxygen?
hemoglobin: iron-containing protein
- binds 4 O2
Sickle cell disease
Caused by abnormal hemoglobin proteins that form aggregates
Deforms erythrocyte into sickle shape that rupture or block blood vessels
Leukocytes (3)
1) 5 major type
2) Play defense by phagocytizing bacteria and by mounting immune responses
3) Found in both in and out of circulatory system
Common feature of different type of blood cells
Develop from a common source of stem cells in red marrow of bones
(ribs, vertebrae, sternum, pelvis)
What stimulates erythrocyte production
Erythropoietin (EPO)
Coagulation
Formation of solid clot from liquid blood
activates fibrinogen to fibrin to form clot
Thrombus
Blood clot formed within a blood vessel, blocks blood flow
Atherosclerosis
Build up of fatty deposits within arteries
Cholesterol is key player
Low-density lipoprotein
Bad
Delivers cholesterol to cells for membrane production
High-density lipoprotein
Good
Scavenges excess cholesterol for return to the liver
What increases risk for heart diseases
high LDL to HDL ratio
What plays a role in cardiovascular disease?
inflammation
Myocardial infarction
The damage or death of cardiac muscle tissue resulting from blockage of coronary arteries
(heart attack)
Stroke
Death of nervous tissue in the brain
resulting from rupture or blockage of arteries in the head
Angina Pectoris
Chest pain caused by partial blockage of the coronary arteries
Gas exchange
Uptake of O2 from the environment
Discharge of CO2 to the environment
Driven by Partial Pressure
Partial Pressure
Pressure exerted by a particular gas in a mixture of gases
Gas exchange occurs
Due to diffusion
Ventilation
Moves the respiratory medium over the respiratory surface
(gills- fish move to put water over their gills)
Countercurrent Exchange
Blood flows in the opposite direction to water passing over gills
Does blood have less O2 saturation than the water it meets
yes
Tracheal system
Network of branching tubes throughout the body
Tracheal tubes
supply O2 directly to body cells
Lungs
Infolding of the body surface
Circulatory system transports gases from lungs to body
What happens to air through the nostrils
Filtered, warmed, humidified and sampled for odor
Pharynx role in respiratory
Directs air to the lungs and food to stomach
Pathway of air passing through our body
Pharynx, larynx, trachea, bronchi, bronchioles to alveoli
What lines epithelium of air ducts
Cilia and mucus
What is the “mucus escalator”
Cleans respiratory system and allows particles to be swallowed into the esophagus
Where does gas exchange happen in mammals?
Alveoli, air sacs at tips of bronchioles
Where does oxygen diffusion through
Moist film of the epithelium into capilllaries
Where does CO2 diffuse from
From Capillaries across the epithelium and into air space
Surfactants
Coat the surface of alveoli
Traits of alveoli
Lack cilia and are susceptible to contamination
Respiratory distress syndrome
Preterm babies lacking surfactant
Amphibians breathe by
Postive pressure breathing
How do birds breathe
Air sacs that function as belows
Air passes through the lungs in one direction only
Passage of air through lungs require two cycles of inhalation and exhalation
How do mammals breathes
Negative pressure breathing
Lung volume increase as rib muscles and diaphragm contract
Tidal Volume
The volume of air inhaled
Vital Capacity
maximum tidal volume
Residual volume
air that remains in the lungs
Breathing controls are found where
Medulla oblongata
Regulates the rate and depth of breathing responding to ph changes in cerebrospinal fluid
What monitor O2 and CO2 levels
Sensor in aorta and carotid arteries
Additional modulation of breathing location
pons
Respiratory pigments
Proteins that transport oxygen, increase amount of oxygen blood can carry
Hemocyanin
Copper as the oxygen-binding component
(arthropods and mollusks)
Most vertebrates use what type of protein in their blood?
Hemoglobin
Bohr Shift
Lowers blood pH and decreases the affinity of hemoglobin for O2
Carbon Dioxide Transport
1) 7% of blood diffuses to hemoglobin
2) remainder diffused into erythrocytes
3) dissociates into H+ and bicarbonate ions
What do diving mammals do to conserve oxygen? (5)
1) Stockpile O2
2) Store oxygen in myoglobin proteins
3) Change their buoyancy to glide passively
4) Route blood to vital tissues
5) Derive ATP in muscles from fementation once oxygen is depleted
