Gas Exchange and Circulation Flashcards
Unicellular
directly exchange with environment
Multicellular
direct exchange with environment is not possible
Exchange occurs at what level?
Occur at cellular level by crossing the plasma membrane
What is an example of a specialized exchange system in animals?
Gills
Relating to gills, how does O2 diffuse?
O2 diffuses from water into blood vessels
Relating to gills, how does CO2 diffuse?
CO2 diffuses from blood into water
Internal transport and gas exchange are functionally related to animals. True or False
True
All animals have a circulatory system. True or False
False. Some animal lack a circulatory system
A gastrovascular cavities functions in both…
digestion and distribution of substances throughout body
Gastrovascular cavities are only one cell wall thick. True or false
False. The body wall that encloses the gastrovascular cavity is only TWO cells thick.
Do flatworms have a gastrovascular cavity?
Yes. Flatworms have a gastrovascular cavity and a large surface area to volume ratio
Three main parts of a circulatory system:
Circulatory fluid Set interconnecting vessels Muscular pump (heart)
Are circulatory systems open or closed?
Circulatory systems can be open or closed (vary number of circuits in the body)
Circulatory systems function:
connects fluid that surrounds cells with organs that exchange gases, absorb nutrients, and disposes of wastes
Open circulatory system
- bathes organs directly
- no direction between blood and interstitial fluid and (general body fluid called hemolymph)
In what animals is it common to have a open circulatory system?
Arthropods, most molluscs, and insects
Closed circulatory system
- confined to vessels and directional from interstitial fluid
- More efficient at transporting fluids to tissues and cells
In what animals it it common to have a closed circulatory system?
Annelids, cephalopods, and vertebrates
Cardiovascular system
closed circulatory system humans and vertebrates have
Main type of blood vessels:
Arteries
Veins
Capillaries
Arteries
Branch from arterioles and carry blood away from the heart
Veins
Venules converge into veins and return blood from capillaries to the heart
Capillaries
Capillary beds- network of capillaries, site of chemical exchange between the blood and interstitial fluid
How many chambers do vertebrate hearts contain?
Vertebrate hearts contain two or more chambers
What vessels are distinguished by the direction of blood flow not by O2 content?
Arteries and veins
Blood enters an _____ and is pumped out through a ______
atrium and ventricle
Single circulation
blood leaving the heart passes thru two capillary beds before returning
Common animals known to have single circulation with two chamber hearts:
bony fish, rays, sharks,
Animals known to have double circulation:
Amphibians, reptiles, and mammals
Double Circulation
Oxygen-poor and rich blood are umped separately from the right and left sides of the heart
In reptiles and mammals, oxygen-poor blood flows through the ______ to pick up oxygen through lungs
Pulmonary circuit
In amphibians, oxygen- poor blood flows through the ________ to pick up oxygen through the lungs and skin
Pulmocutaneous circuit
In what animals is it common to have a three-chamber heart?
Turtles, snakes, lizards, frogs, and other amphibians
How does a three- chamber heart function?
- The ventricle pumps blood into a forked artery that splits the ventricle’s output into the pulmocutaneous circuit and the systemic circuit
- Blood flow to lungs is nearly shut off
Reptiles have double circulation, with a pulmonary circuit (lungs) and a systemic circuit. True or false
True
Form of a three-chamber heart
a three-chambered heart: two atria and one ventricle
Alligators, caimans and other crocodilians have a septum that divides the ventricle. True or false
True
Reptiles (except birds) have a double- circulation. True or False
True. Retiles have double circulation, with pulmonary circuit (lungs) and systemic circuit.
What kind of chambered heart do birds and mammals have?
Mammals and birds have a four-chambered heart with two aria and two ventricles
How does a four-chambered heart function?
The left side of the heart pumps and receives only oxygen-rich blood, while the right side receives and pumps only oxygen-poor blood
Ectotherms require more O2 than endotherms. True or False
False. Mammals and birds are endotherms and require more O2 than ectotherms
How does the blood flow in a mammalian circulatory system?
Blood begins its flow with the right ventricle pumping blood to the lungs
In the lungs, the blood loads O2 and unloads CO2
Oxygen-rich blood from the lungs enters the heart at the left atrium and is pumped through the aorta to the body tissues by the left ventricle
The aorta provides blood to the heart through the coronary arteries
Blood returns to the heart through the superior vena cava (blood from head, neck, and forelimbs) and inferior vena cava (blood from trunk and hind limbs)
The superior vena cava and inferior vena cava flow into the right atrium
cardiac cycle
The heart contracts and relaxes in a rhythmic cycle
diastole
relaxation or filling of the heart
systole
contraction or pumping of the heart
heart rate (pulse)
number of heart beats per minute
stroke volume
amount of blood pumped in a single contraction
cardiac output
volume of blood pumped into the systemic circulation per minute and depends on both the heart rate and stroke volume
How many valves prevent backflow of blood in the heart?
Four valves
What do the atrioventricular (AV) valves do?
separate each atrium and ventricle
Semilunar valves
control blood flow to the aorta and the pulmonary artery
The “lub-dup” sound of a heart beat is caused by the…
recoil of blood against the AV valves (lub) then against the semilunar (dup) valves
What causes heart murmurs?
backflow of blood through a defective valve
What does the sinoatrial (SA) node, or natural pacemaker do?
sets the rate and timing at which cardiac muscle cells contract
What does it mean when cardiac muscle cells are self-excitable?
contract without any signal from the nervous system
What are electrocardiograms (ECG or EKG) used for?
record impulses that travel during the cardiac cycle
Where do impulses from the SA node travel to?
the atrioventricular (AV) node
Where do the impulses travel after the AV node?
to the Purkinje fibers that make the ventricles contract
The sympathetic division
speeds up the pacemaker
What two portions of the nervous system regulate the pacemaker?
- sympathetic and parasympathetic
divisions - hormones and temperature
The parasympathetic division
slows down the pacemaker
What is the epithelial layer that lines blood vessels is called?
the endothelium
- endothelium is smooth and minimizes resistance
What is a vessel’s cavity called?
central lumen
Plasma proteins function in
- Lipid transport, immunity, and blood clotting
Lymph nodes are:
- Organs that filter lymph and play an important role in the body’s defense
What do valves in lymph vessels prevent?
- Backflow of fluid
Lymph:
- Fluid reenters the circulation directly at the venous end of the capillary bed and indirectly through the lymphatic system
Lymphatic system:
Returns fluid that leaks out from the capillary beds
- Drains into veins in the neck
Platelets are
- A third cellular element, are fragments of cells that are involved in clotting
Blood supply varies in many other sites. True or False
True
Most blood proteins and all blood cells are too large to pass through the endothelium. True or False
- True
What percent of blood plasma is water?
- About 90% water
Edema is:
- Swelling caused by disruptions in the flow of lymph
Plasma:
- Liquid matrix blood consists of several kinds of cells suspended
Endothelium, smooth muscle, and connective tissue are all element of what blood vessels?
- Arteries and veins
What percent of cellular elements occupy the volume of blood?
- 45 percent
Red blood cells (erythrocytes)
- Transport oxygen O2
How is blood pressure determined?
- By cardiac output and peripheral resistance due to constriction of arterioles
Vasoconstriction
- Is the contraction of smooth muscle in arteriole walls; it increases blood pressure
Thrombus is:
- A blood clot formed within a blood vessel and can block blood flow
What forms a clot?
- A cascade of complex reactions converts inactive fibrinogen to fibrin, forming a clot
White blood cells (leukocytes)
- Function in defense
Coagulation is:
- The formation of a solid clot from liquid blood
Plasma proteins:
- Important class of solutes is the plasma proteins, which influence blood pH, osmotic pressure, and viscosity
Inorganic salts in the form of dissolved ions
-Electrolytes
Vasodilation
- Is the relaxation of smooth muscles in the arterioles; it causes blood pressure to fall
Lungs are an infolding of the body surface
- Circulatory system (open or closed) transports gases between the lungs and the rest of the body
- The size and complexity of lungs correlate with an animal’s metabolic rate
Tracheal system of insects
- Tiny branching tubes that penetrate the body
- Tracheal tubes supply O2 directly to body cells
- Respiratory and circulatory systems are separate
- Larger insects must ventilate their tracheal system to meet O2 demands
Countercurrent exchange
- Blood flows in the opposite direction to water passing over the gills; blood is always less saturated with O2 than the water it meets- Fish sill use
Ventilation
- Moves the respiratory medium over the respiratory surface
Aquatic animals move through water or move water over their gills for ventilation
Partial pressure is
- The pressure exerted by a particular gas in a mixture of gases
A gas diffuses from a region of higher partial pressure to a region of lower partial pressure. True or False
- True
- Example. Gases diffuse down pressure gradients in the lungs and other organs as a result of differences in partial pressure
Why do capillaries have thin wall? And what are the walls called?
- To facilitate the exchange of materials
- Endothelium and basal lamina
Gas exchange
- Supplies O2 for cellular respiration and disposes of CO2
What is the function of one-way valves in veins?
- Prevent backflow of blood
- Assist in return of deoxygenated blood
Do arteries have thicker walls than veins? True or False
- True. To accommodate the high pressure of blood pumped from the heart
What is blood pressure?
- Blood pressure is the pressure that blood exerts against the wall of a vessel
What does hemoglobin also help do in the body?
helps transport CO2 and assists in buffering the blood
Respiratory pigments:
proteins that transport oxygen, greatly increase the amount of oxygen that blood can carry
Examples
-Arthropods and many molluscs have hemocyanin with copper as the oxygen-binding component
Most vertebrates and some invertebrates use hemoglobin
In vertebrates, hemoglobin is contained within erythrocytes
vital capacity
The maximum tidal volume
Bohr shift
CO2 produced during cellular respiration lowers blood pH and decreases the affinity of hemoglobin for O2
negative pressure breathing
pulls air into the lungs what mammals do to ventilate their lungs
tidal volume
volume of air inhaled with each breath
residual volume
After exhalation, amount of air that remains in the lungs
positive pressure breathing
forces air down the trachea what an amphibian such as a frog ventilates its lungs
breathing is
The process that ventilates the lungs, the alternate inhalation and exhalation of air
Air passes through the…
pharynx, larynx, trachea, bronchi, and bronchioles to the alveoli, where gas exchange occurs
“mucus escalator”
cleans the respiratory system and allows particles to be swallowed into the esophagus
(Cilia and mucus line the epithelium of the air ducts and move particles up to the pharynx)
