Chapter 42 Circulation and Gas Exchange Flashcards
How do small molecules move between cells and their environment?
Via diffusion (doesn’t need energy)
Why is diffusion only efficient over small distances?
B/c the time it takes for diffusion to occur is proportional to the square of the distance
What does the gastrovascular cavity function in?
Functions in both digestion and distribution of substances throughout the body
Differences b//w exchange systems of small/thin animals and other animals
Small/thin animals: Able to easily exchange materials with the environment
Other animals: Exchange materials with environment via fluid-filled circulatory system
What kind of cavity does flatworms have?
They have a gastrovascular cavity; flat body minimizes diffusion distances
What are the 3 things found in a circulatory system?
- circulatory fluid
- set of interconnecting vessels
- muscular pump (heart)
What are the functions of the circulatory system? (3)
- connects fluid that surrounds cells with organs that exchange gases
- absorb nutrients
- dispose of wastes
What happens during a closed circulatory system?
Blood is confined to vessels and is distinct from the interstitial fluid
What happens during open circulatory system?
Circulatory fluid (hemolymph) bathes organs directly
What species have open circulatory system?
- arthropods and some molluscs
What species have a closed circulatory system?
- Annelids, cephalopods, and vertebrates
What is the cardiovascular system?
Closed circulatory system found in humans and other vertebrates
What are the 3 types of blood vessels?
- capillaries
- arteries
- veins
What are arteries?
Blood vessels that takes blood away from the heart
What direction does blood move in blood vessels?
Blood flow is one direction
What are veins?
Blood vessels that take blood toward the heart
What are capillaries?
Smallest blood vessels where the exchange of materials and gas occurs
Explain connection b/w arteries, aterioles, and capillaries
Arteries branch into arterioles and carry blood away from the heart to capillaries
What are the smallest arteries?
Arterioles
Capillaries are b/w what 2 blood vessels?
Arterioles and venules
What are the smallest veins?
Venules
What are capillary beds?
Network of capillaries that are the sites of chemical exchange b/w blood and interstitial fluid
What do venules do?
converge into veins and return blood from capillaries to the heart
How does blood enter and exit?
Enters via the atrium; exits via the ventricle
How are arteries and veins distinguished?
By the direction of blood flow
What do vertebrate hearts contain?
2 or more chambers
What happens during single circulation? What species can we see this?
Blood leaves the heart and passes thru two capillary beds before returning
Bony skeleton fishes (examples)
What is double circulation? What species can this be found?
Oxygen-poor and oxygen-rich blood are pumped separately from the right and left sides of the heart
Amphibians, reptiles, and mammals (example)
Right side of heart is what kind of oxygen? Left side of heart is what kind of oxygen? (Double circulation)
Right side: Oxygen poor blood
Left side: Oxygen rich blood
What is significant pulmonary arteries?
Pulmonary arteries contain oxygen poor blood (goes to lungs) while the rest of the arteries contain oxygen rich blood
What are the chambers called?
Atrium and ventricles
Difference b/w atrium and ventricles?
Atrium: Receiving chamber (upper chamber)
Ventricles: Pumping chamber (lower chamber)
Difference b/w right and left side of heart
The left side of the heart pumps and receives only oxygen-rich blood, while the right side receives and pumps only oxygen-poor blood
Explain the heart layout of turtles, snakes, and lizards
have a three-chambered heart: two atria and one ventricle, partially divided by an incomplete septum
How many pulmonary veins do we have?
4 (two from each lung)
Where do the pulmonary veins open to?
Open to the left atrium
Explain the steps of the cardiovascular system
- Blood comes from below and above diaphragm via the superior and inferior vena cava to the right atrium. Blood is deoxygenated.
- Blood travels to right ventricle from right atrium via the tricuspid valve.
- Blood leaves the right ventricle to the capillaries of lungs via the pulmonary arteries. Blood is still deoxygenated.
- Blood is now oxygenated and leaves lungs via pulmonary veins, 4 veins in total. Goes to the left atrium.
- Blood goes to the left ventricle from left atrium.
- Blood is then pumped throughout body from left ventricle via the aorta.
What is systole?
Contraction or pumping phase
What is diastole?
Relaxation or filling phase
What is cardiac cycle?
Heart contracts and relaxes in rhythmic cycle
Normal systolic/diastolic
120/80
What is heart rate (pulse)?
Number of beats per minute
What is the stroke volume?
The amount of blood pumped in a single contraction/pump
What is cardiac output?
volume of blood pumped into the systemic circulation per minute and depends on both the heart rate and stroke volume
What are atrioventricular valves?
Valves that separate each trium and ventricle
What are semilunar valves?
Valves that control blood flow to the aorta and pulmonary artery
What is the “lub-dup” sound of a heartbeat caused by?
caused by the recoil of blood against the AV valves (lub) then against the semilunar (dup) valves
What causes a heart murmur?
Backflow of blood through a defective valve
What is sinoatrial (SA) node?
Also known as pacemaker, which sets the rate and timing at which cardiac muscle cells contract
What is the electrocardiogram (ECG/EKG)?
Recording of electrical impulses that travel during the cardiac cycle
Explain the steps of the heartbeat in an ECG
- Signals from the SA node spread throughout atria
- Signals are delayed at the AV node
- Bundle branches pass signals to the heart apex
- Signals are spread throughout ventricles via Purkinje fibers
Difference b/w parasympathetic and sympathetic in terms of pacemaker
Parasympathetic: Decreases pacemaker
Sympathetic: Increases pacemaker
What is endothelium?
Epithelial layer that lines blood vessels
What are vessel’s cavity called?
Central lumen
What is parasympathetic? What is sympathetic?
Parasympathetic: Rest and digest
Sympathetic: Flight or fight
Describe characteristics of capillaries (2)
- thin walls that facilitate the exchange of materials
- The thin walls are made up of endothelium and basal lamina
Describe characteristics of arteries and veins
- Have endothelium, smooth muscle and connective tissue
Why do arteries have thicker walls than veins?
To accommodate the high pressure of blood pumped from the heart
Describe blood flow in blood vessels
Blood goes from the artery to the arteriole and then to the capillary. From the capillary it goes to the venule and then to the vein.
What is systolic pressure?
pressure in the arteries during ventricular systole; it is the highest pressure in the arteries
What is diastolic pressure?
the pressure in the arteries during diastole; it is lower than systolic pressure
What is pulse?
Rhythmic bulging of artery walls with each heartbeat
What is vasoconstriction?
contraction of smooth muscle in arteriole walls; it increases blood pressure
What is vasodilation?
is the relaxation of smooth muscles in the arterioles; it causes blood pressure to fall
Difference b/w when sphincters are relaxed vs contacted
- When relaxed, blood travels throughout the capillary bed.
- When contracted, blood travels one way directly to the venule from arteriole.
What is the difference b/w blood pressure and osmotic pressure?
Blood pressure pushes water out of the capillaries at the arteriole end
Osmotic pressure pulls water in capillaries at the venule end
What is the lymphatic system?
System that returns fluid that leaks out from the capillary beds?
What is fluid lost by capillaries called?
Lymph
What are lymph nodes?
Organs that filter lymph and play an important role in the body’s defense
What is plasma?
A liquid matrix that has several kinds of cells suspended
What is the composition of blood?
45% are cellular elements (red blood cells, white blood cells, and platelets)
55% is plasma
What are the 5 types of leukocytes?
- basophils
- neutrophils
- monocytes
- lymphocytes
- eosinophils
How many molecules of oxygen does each molecule of hemoblobin carry?
up to 4 molecules of oxygen
What does particular plasma proteins function in? (3)
- lipid transport
- immunity
- blood clotting
What are platelets?
Fragments of cells that are involved in clotting
What are erythrocytes?
Red blood cells
What is hemoglobin?
Iron-containing protein that transports oxygen in red blood cells
What is sickle-cell disease causes by?
Caused by an abnormal hemoglobin proteins that form aggregates which deforms red blood cells into a sickle shape
What are leukocytes?
White blood cells
What are stem cells?
Cells in red bone marrow that develop into red blood cells, white blood cells, and platelets
What is erythropoietin?
A hormone that stimulate erythrocyte production when oxygen delivery is low.
How does blood clot happen?
Complex reactions converts inactive fibrinogen to fibrin
What is a thrombus?
Blood clot formed within a blood vessel
What is atherosclerosis?
A type of cardiovascular disease that’s caused by the buildup of fatty deposits (plaque) within arteries
Difference b/w low density lipoprotein vs high density lipoprotein
LDL delivers cholesterol to cells for membrane production vs. HDL scavenges excess cholesterol for return to liver
What is a heart attack?
the damage or death of cardiac muscle tissue resulting from blockage of one or more coronary arteries
What is a stroke?
death of nervous tissue in the brain, usually resulting from rupture or blockageof arteries in the head
What is hypertension?
High blood pressure that also contributes to heart attacks and stroke, as well as other health problem
What is gas exchange?
Supplies oxygen for cellular respiration and dispose of carbon dioxide
What is partial pressure?
Pressure exerted by a particular gas in a mixture of gases
What does ventilation do?
moves the respiratory medium over the respiratory surface
What is countercurrent exchange system?
where blood flows in the opposite direction to water passing over the gills –> occurs in fish
What is the tracheal system?
Breathing system of insects
What are lungs?
Infoldings of the body surface
Where does gas exchange occur?
In the alveoli only
What is the direction that air flows to?
From the pharynx to larynx to trachea to bronchi to bronchioles to alveoli
What is breathing?
Alternation b/w inhalation and exhalation of air that ventilates the lungs
How do amphibians breathe?
By positive pressure breathing, which forces air down the trachea
How does a bird breathe?
Via 2 cycles of inhalation and exhalation
How does a mammal breathe?
Ventilates their lungs via negative pressure breathing which pulls air into lungs
What is tidal volume?
Volume of air inhaled with each breath
What is vital capacity?
Maximum tidal volume
What is residual volume?
The volume of air that remains in the lungs after exhalation
Inhalation vs exhalation in terms of diaphragm
Inhalation: Diaphragm contracts (moves down)
Exhalation: Diaphragm relaxes (moves up)
Where do diving mammals store their oxygen?
Stores it in their muscles in myoglobin proteins
What is Bohr shift?
CO2 produced during cellular respiration lowers blood pH and decreases the affinity of hemoglobin for O2
Is the right side or left side of the heart thicker?
Left side is thicker because it pumps blood to the whole body.
What is the systemic circuit?
Carries deoxygenated blood to heart and pumps oxygenated blood throughout body
What is the pulmonary circuit?
Carries deoxygenated blood from the heart to the lungs; and carries oxygenated blood from the lungs back to the heart
