Chapter 42 - Circulation and Gas Exchange

How do small molecules move between cells and surroundings?

Diffusion

What is the drawback for diffusion?

It is only efficient over small distances

What do animals who lack a circulatory system have?

Gastrovascular cavities

What functions in both digestion and distribution of substances throughout the body?

Gastrovascular cavities

What 3 things do a circulatory system have?

1. circulatory fluid
2. set of interconnecting vessels
3. muscular pump, the heart

What connects the fluid that surrounds cells with organs that exchange gases, absorb nutrients, and dispose of wastes?

Circulatory system

What 2 ways can the circulatory system be?

1. Open
2. Closed

What is the circulatory fluid that bathes organs in an open circulatory system in some animals?

Hemolymph

What 3 animals have hemolymph fluid?

Insects, arthropods, molluscs

Blood is confined to vessels and is distinct from the interstitial fluid in what kind of circulatory system?

Closed

Humans and other vertebrates have a closed circulatory system called the what?

Cardiovascular system

What does the cardiovascular system include?

1. heart
2. blood vessels

What are the 3 types of blood vessels?

1. arteries
2. veins
3. capillaries

What do arteries branch into?

Arterioles

Where do arteries carry blood to?

Away from the heart to capillaries

What is a network of capillaries called?

Capillary beds

What do venules converge into?

Veins

What do veins take blood?

From the capillaries to the heart

Where does blood enter?

Atria

Where is blood pumped out through?

Ventricles

What form of circulation has blood leave the heart and pass through 2 capillary beds before returning?

Single circulation

What animals have single circulation with a two-chambered heart?

Sharks, rays, and bony fish

What form of circulation has no separation of oxygenated and deoxygenated blood?

Single circulation

What animals have double circulation?

Amphibians, reptiles, and mammals

What form of blood circulation maintains higher blood pressure in the organs?

Double circulation

Why does double circulation maintain higher blood pressure in the organs?

It passes through only one capillary bed

What side of the heart if oxygen-poor blood pumped from?

Right

What side of the heart is oxygen-rich blood pumped from?

Left

In amphibians, what circuit does oxygen-poor blood flow through to pick up oxygen via the lungs and skin?

Pulmocutaneous circuit

In reptiles and mammals, oxygen poor blood flows through what circuit to pick up oxygen from the lungs?

Pulmonary circuit

How are some vertebrates intermittent breathers?

It can breathe through the skin

How many chambers do amphibians have?

3

What are the 3 chambers of the amphibian heart?

Two atria and one ventricle

How many chambers does a mammal and bird heart have?

4

What do coordinated cycles of heart contraction drive in mammals?

Double circulation

What is the cycle in which the heart contracts and relaxes in a rhythmic cycle?

Cardiac cycle

What is the contraction or pumping phase called?

Systole

What is the relaxation or filling phase called?

Diastole

How is blood pressure measured?

Systolic/Diastolic

What is the volume of blood pumped into the systemic circulation per minute and depends on both the heart rate and stroke volume?

Cardiac output

What is the number of beats per minute?

Heart rate

What is the amount of blood pumped in a single contraction?

Stroke volume

What prevents backflow of blood into the hearts?

Valves

What valves separate each atrium and ventricle?

Atrioventricular valves

What controls the blood flow to the aorrta and pulmonary artery?

Semilunar valves

What sound does the recoil of blood against the Atrioventricular valves cause?

Lub

What sound does the recoil of blood against the semilunar valves?

Dup

What does the backflow of blood through a defective valve cause?

Heart murmur

What does it mean when a cardiac muscle contracts without any signal from the nervous system?

Autorhythmic

What sets the rate and timing at which cardiac muscle cells contract?

Pacemaker

What is another name for a pacemaker?

Sinoatrial node

What are the impulses that travel during the cardiac cycle recorded as?

Electrocardiogram (EKG)

Where do impulses from the sinoatrial node (pacemaker) travel to?

Atrioventricular node

Where are the impulses located?

Atrioventricular node

Where do impulses travel to from the atrioventricular node?

Purkinje fibers

What makes the ventricles contract?

Purkinje fibers

What do patterns of blood pressure and flow reflect in the blood vessels?

Structure and arrangement

What is the epithelial layer that lines blood vessels called?

Endothelium

How does endothelium minimize resistance?

By being smooth

What is only slightly wider than a red blood cell?

Capillaries

Why do capillaries have thin walls?

To facilitate the exchange of materials

What blood vessel has valves?

Veins

Why do veins have thinner walls?

They take blood back to the heart at a lower pressure

Why do arteries have thicker, elastic walls?

To accommodate the higher pressure it takes to pump blood away from the heart

What happens to the speed as it moves from larger vessels to smaller vessels?

Slows down

Blood flows in what direction of pressure?

High to low

What is the pressure in the arteries during ventricular systole called?

Systolic pressure

What is the rhythmic bulging of artery walls within each heartbeat?

Pulse

What is the pressure in the arteries during diastole (when the ventricles are relaxed)?

Diastolic pressure

What is the narrowing of arteriole walls?

Vasoconstriction

What is the widening of arterioles?

Vasodilation

What is a major inducer of vasodilation?

Nitric oxide

What is a potent inducer of vasodilation?

Peptide endothelin

What is caused by an inadequate blood flow to the head?

Fainting

What system returns fluids that leaked out from the capillary beds?

Lymphatic system

What is the fluid lost by capillaries called?

Lymph

What are organs that filter lymph and play an important role in the body’s defense?

Lymph nodes

What is swelling caused by disruptions in the flow of lymph?

Edema

What do blood components function in? (3)

1. Exchange
2. Transport
3. Defense

What is the liquid matrix that cells are suspended in within the blood in vertbrates?

Plasma

What percentage of blood does plasma make?

45

Chart

What are the fragments of cells involved in clotting?

Platelets

What is another name for red blood cells?

Erythrocytes

What is the iron-containing protein that transports oxygen?

Hemoglobin

What is caused by abnormal hemoglobin proteins that form aggregates?

Sickle-cell disease

Why is it called sickle cell disease?

The aggregates deform RBC into a sickle shape

What can occur to sickled cells?

They can rupture or block blood vessels

What happens to the RBC supply in individuals with sickle cell disease?

Reduces it

What is another name for white blood cells?

Leukocytes

What are the 2 ways WBC function in defense?

1. Phagocytosis
2. Mounting immune responses

Where are stem cells located?

Bone marrow

What hormone stimulates erythrocyte production when oxygen delivery is low?

Erythropoietin

What cells make up lymphocytes?

B cells and T cells

What is a blood clot formed in a blood vessel called?

Thrombus

What is the hardening of the arteries, caused by the buildup of fatty deposits within the arteries?

Atherosclerosis

What is the damage or death of cardia muscle tissue resulting in blockage of one or more coronary arteries?

Heart attack

What is the death of nervous tissue in the brain, usually resulting from rupture or blockage of arteries in the head?

Stroke

What delivers cholesterol to cells for membrane production?

Low-density lipoprotein

What scavenges excess cholesterol for return to the liver?

High-density lipoprotein