Animal Form and Function Flashcards
What are tissues?
Groups of similar cells performing a common function
What are the 4 general categories of animal tissues?
1) Epithelial (outer skin layers and internal protective coverings)
2) Connective (bone, cartilage, blood)
3) Nervous
4) Muscle
What is an organ?
A group of different kinds of tissues functioning together to perform a particular activity (i.e. heart)
What is an organ system?
Two or more organs working together to accomplish a particular task (i.e. digestive system)
What is homeostasis?
The maintenance of stable, internal conditions within narrow limits.
How does negative feedback work? (What are the key players?)
A RECEPTOR detects changes in conditions beyond specific limits. The INTEGRATOR (or control center) evaluates the change and actives an EFFECTOR to correct the condition.
What are ectotherms?
AKA, EX
Animals that obtain body heat from the environment. They are sometimes referred to as POIKILOTHERMS (“changing temperature”). Examples: most invertebrates, amphibians, reptiles, and fish. Called “cold-blooded” because they may feel cold to the touch.
What are endotherms?
AKA
Animals that produce their own body heat. Referred to as HOMEOTHERMS because they maintain a constant internal temperature, or “warm-blooded” because they are warm compared to ectotherms.
What mechanisms are used by animals to regulate body temperature?
1) Cooling by evaporation: sweating or panting
2) Warming by metabolism: muscle contractions (i.e. shivering) and other metabolic activities generate heat
3) Adjusting surface area to regulate temperature: changing the volume of blood flowing to arms, hands, feet, and ears through vasodilation/vasoconstriction to maintain or release heat; countercurrent exchange of heat in blood to/from extremities to conserve heat.
What are vasodilation and vasoconstriction?
Increasing or decreasing the diameter of blood vessels
What is the function of the respiratory system?
Delivering O2 and removing CO2. Generally, RESPIRATION is the movement of gases into and out of the organism.
What mechanisms are used for gas exchange in animals?
1) Direct with environment: Some animals have large enough surface areas to allow gas exchange directly with the outside environment. Diffusion can bring gas to adjacent cells in small animals (i.e. Platyhelminthes, flatworms). Larger animals (i.e. Annelida, segmented worms) also use a distribution system inside the skin.
2) Gills
3) Tracheae
4) Lungs
What are gills?
Evaginated structures that creates a large surface area for gas exchange to occur. They can be external or internal. A circulatory system inside gills removes oxygen and delivers waste CO2. Countercurrent exchange maximizes diffusion between blood and water.
What are tracheae?
Chitin-lined tubes that permeate insect bodies. Oxygen enters and CO2 exits the tracheae through openings called SPIRACLES. Diffusion occurs across moistened tracheal endings.
What are lungs?
Invaginated structures within an animal.
What are invaginated structures?
Cavities within the body of an animal.
What are evaginated structures?
Outgrowths from the body
What are operculum?
Gill covers in fish where water exits after passing over the gills.
What are book lungs?
Stacks of flattened membranes enclosed in an internal chamber. Present in spiders.
What are spiracles?
Tracheae openings through which oxygen enters and CO2 exits
What structures are involved in gas exchange in humans?
1) Nose, pharynx, larynx
2) Trachea
3) Bronchi, bronchioles
4) Alveolus (p: alveoli)
5) Lungs (diaphragm and intercostal muscles)
What is the pharynx?
Nasal cavity
What is the larynx?
“voice box” that contains the vocal cords
What is the trachea?
A cartilage-lined tube through which air passes. The EPIGLOTTIS cover the trachea when swallowing to prevent solids and liquids from entering.
What is the epiglottis?
A flap that covers the trachea when swallowing to prevent entrance of solids and liquids.
What are bronchi (s: bronchus)?
The trachea branches into 2 bronchi, which enter the lungs and then branch repeatedly into narrower tubes called BRONCHIOLES.
What are bronchioles?
Narrower tubes resulting from the branching of bronchi.
What is the alveolus (p: alveoli)?
A small sac at the end of each bronchiole. It is densely surrounded by blood-carrying capillaries.
How does air enter the lungs? Describe bulk flow of air into and out of the lungs (mechanics of respiration).
When the diaphragm and intercostal muscles contract, lung volume increases, air pressure decreases, and air rushes into the lungs through bulk flow. When the muscles relax, the volume decreases, increasing air pressure, and air rushes out. Air passes through the nose, pharynx, larynx, trachea, bronchi, bronchioles, and alveoli membranes.
What is the diaphragm?
A muscle under the lungs
What are intercostal muscles?
Muscles between the ribs
How does air diffuse into blood?
Oxygen diffuses across the moisture covering the alveolus membrane, then the alveolar wall, through the blood capillary wall, into the blood, and into red blood cells. Carbon dioxide diffuses in the opposite direction.
How is oxygen circulated in the body? (Describe the bulk flow of oxygen.)
The circulatory system transports oxygen throughout the blood within red blood cells, where they bind to iron-containing proteins called hemoglobin.
How do oxygen and carbon dioxide diffuse from blood to cells?
Oxygen diffuses out of the RBC, across blood capillary walls throughout the body, into interstitial fluids (the fluid surrounding cells), and across cell membranes. Carbon dioxide diffuses in the opposite direction.
How is carbon dioxide transported in the body? (Describe the bulk flow of carbon dioxide.)
While most CO2 is transported as dissolved bicarbonate ions (HCO3-) in plasma, some CO2 gas mixes directly with plasma or binds with amino groups of hemoglobin. Formation of bicarbonate ions occurs in RBC, where carbonic anhydrase catalyzes the formation of carbonic acid (H2CO3), and then the ions diffuse back into plasma. CO2 + H2O –> H2CO3 –> H+ + HCO3-
How is respiration controlled?
Chemoreceptors in the carotid arteries monitor blood pH. CO2 production increases when the body is active, and as a result, blood pH drops. The chemoreceptors send nerve impulses to the diaphragm and intercostal muscles to increase the respiratory rate, increasing gas exchange to return pH to normal.
What are the carotid arteries?
Arteries that supply blood to the brain
What is the function of the open circulatory system?
- In insects and most mollusks
- Blood is pumped into an internal cavity called a HEMOCOEL (or cavities called SINUSES), which bathe tissues with an oxygen- and nutrient-carrying fluid called HEMOLYMPH.
- Hemolymph returns to the heart, which is the pumping mechanism of the system, through holes called OSTIA
What is the function of the closed circulatory system?
- In members of the phylum Annelida (i.e. earthworms), certain mollusks (octopuses and squids), and vertebrates
- The nutrient-, oxygen-, and waste-carrying fluid, blood, is confined to vessels
What vessels carry blood away from the heart in the closed circulatory system of vertebrates?
Vessels moving away from the heart are called ARTERIES, which branch into smaller vessels called ARTERIOLES, which branch into the smallest vessels, called CAPILLARIES.
What vessels carry blood back to the heart in the closed circulatory system of vertebrates?
Blood returns to the heart through VENULES, which merge to form larger VEINS.
What is the general path of blood in the closed circulatory system of vertebrates?
Heart –> arteries –> arterioles –> capillaries –>cells –> capillaries –> venules –> veins –> heart –> arteries –> arterioles –> capillaries –> lungs/gills –> veins –> heart –> repeat
How does blood move through the human heart?
Right atrium –> right ventricle –> lungs–> left atrium –> left ventricle –> aorta –> rest of body
What occurs in the right atrium?
Deoxygenated blood enters through 2 veins, the upper SUPERIOR VENA CAVA and the lower INFERIOR VENA CAVA before moving to the right ventricle.
What occurs in the right ventricle?
Deoxygenated blood moves from the right atrium through the RIGHT ATRIOVENTRICULAR (AV) VALVE, aka tricuspid valve, into the right ventricle, whose walls are thicker and more muscular than those of the atria. The walls contract and pump blood into the PULMONARY ARTERY, through the PULMONARY SEMILUNAR VALVE, towards the lungs. When the ventricles contract, the AV valve closes and prevents blood moving backward into the atrium. When they relax, the semilunar valve prevents back flow from the pulmonary artery back into the ventricles.
What does the pulmonary semilunar valve do?
It prevents blood from the pulmonary artery back into the right ventricle when the ventricle relaxes.
What does the right atrioventricular (AV) valve do?
AKA
AKA tricuspid valve
Prevents blood from moving backward from the right ventricle to right atrium when the ventricle contracts.
What is the pulmonary artery?
The artery that carries deoxygenated blood from the heart to the lungs.
What occurs in the left atrium?
Oxygenated blood returns to the left atrium through the PULMONARY VEINS.
What is the pulmonary vein?
The vein that carries oxygenated blood from the lungs to the heart.
What occurs in the left ventricle?
Blood moves from the left atrium through the LEFT ATRIOVENTRICULAR (AV) VALVE, aka mitral or biscupid valve), into the left ventricle, The ventricle pumps blood into the AORTA, through the AORTIC SEMILUNAR VALVE, and throughout the body. The left AV valve prevents blood from flowing back into the atrium, and the semilunar valve prevents blood from flowing back into the ventricle.
What does the left atrioventricular (AV) valve do?
AKA
AKA mitral or bicuspid valve
Prevents blood from flowing back from the left ventricle into the left atrium when the ventricle contracts.
What does the aortic semilunar valve do?
Prevents blood from flowing back from the aorta into the left ventricle.
What is the pulmonary circuit?
The blood pathway between the right side of the heart, to the lungs, and back to the left side of the heart.
What is the systemic circuit?
The blood circulation pathway throughout the body (between the left and right sides of the heart).
What is the cardiac/heart cycle?
The rhythmic contraction and relaxation of heart muscles, regulated by specialized tissues in the heart called AUTORHYTHMIC CELLS.
What are autorhythmic cells?
Specialized tissues in the heart that are self-excitable and able to initiate contractions without external stimulation by nerve cells.
What are the steps of the cardiac/heart cycle?
1) The SA (SINOATRIAL) NODE, aka pacemaker, spontaneously initiates the cycle by simultaneously contracting both atria and sending delayed impulse that stimulates the AV (ATRIOVENTRICULAR) NODE.
2) The AV node in the lower wall of the right atrium sends an impulse through the bundle of His, resulting in the contraction of the ventricles.
3) Contraction of the ventricles (the SYSTOLE phase) forces blood through the pulmonary arteries and aorta. When the ventricles relax, it is in the DIASTOLE phase. The closing of the valves produces the “lub-dup” sounds of the heart.
What is the SA (sinoatrial) node?
AKA
AKA pacemaker
Located in the upper wall of the right atrium, it spontaneously initiates the cardiac/heart cycle by simultaneously contracting both atria and sending a delayed impulse that stimulates the AV (atrioventricular) node.
What is the AV (atrioventricular) node?
Located in the lower wall of the right atrium, it sends an impulse through the bundle of His, nodal tissue that passes down between both ventricles and then branches into ventricles through the PURKINJE FIBERS. This results in contraction of the ventricles.
What is the bundle of His?
Nodal tissue that passed down between both ventricles and branches into ventricles through the Purkinje fibers. Impulses sent from the AV node through it results in the contraction of the ventricles.
What is the systole phase?
When the ventricles contract, forcing blood through the pulmonary arteries and aorta. AV valves are forced closed.
What is the diastole phase?
When the ventricles relax. The semilunar valves are forced closed.
What causes blood to move through the arteries?
Hydrostatic pressure created by the heart
What causes blood to move through the veins?
Movement of adjacent skeletal muscles squeeze the blood vessels, and valves in the veins prevent back flow to move blood in the direction of the heart. It is NOT because of the contractions of the heart.
What is the lymphatic system?
A network of capillaries and veins that return fluids (wastes and excess interstitial fluids) to the circulatory system and lymph nodes act as filters.
What is lymph? How does it move through the lymphatic system?
Lymph is the fluid in lymphatic veins. It moves slowly through lymphatic vessels by the contraction of adjacent muscles, while valves prevent back flow. It returns to the blood circulatory system through two ducts located in the shoulder region.
What are lymph nodes?
Enlarged bodies throughout the lymphatic system that act as cleaning filters for lymph and immune response centers that defend against infection.
What are the contents of blood?
1) erythrocytes (red blood cells)
2) leukocytes (white blood cells)
3) platelets
4) plasma
What do red blood cells do? What is another name for them?
AKA erythrocytes
They transport oxygen attached to hemoglobin and catalyze the conversion of carbon dioxide and water to carbonic acid. Mature RBC lack a nucleus, maximizing hemoglobin content and ability to transport oxygen.