Exam 3 Phys: Chapter 17-21

What is the primary function of the cardiovascular system?

transport of materials to and from all parts of the body

1. nutrients, water, and gases that enter the body from the external env

2. materials that move from cell to cell within the body

3. wastes that the cells eliminate

Materials entering the body

Substance moved: oxygen

from → to

lungs to all cells

Materials entering the body

Substance moved: nutrients and water

from → to

intestinal tract to all cells

Materials moved from cell to cell

Substance moved: wastes

from → to

some cells to liver for processing

Materials moved from cell to cell

Substance moved: immune cells, antibodies, clotting proteins

from → to

present in blood continuously to available to any cell that needs them

Materials moved from cell to cell

Substance moved: hormones, neurohormones, and cytokines

from → to

endocrine and neuroendocrine cells; any cell secreting cytokines to target to cells

Materials moved from cell to cell

Substance moved: stored nutrients

from → to

liver and adipose tissue to all cells

Materials leaving the body

Substance moved: metabolic wastes

from → to

all cells to kidneys

Materials leaving the body

Substance moved: heat

from → to

all cells to skin

Materials leaving the body

Substance moved: carbon dioxide

from → to

all cells to lungs

What is the cardiovascular system?

the heart, the blood vessels (vasculature) and the cells and plasma of the blood

What is the atrium?

receives blood returning to the heart

What is the ventricle?

pumps blood out into the blood vessels

What is pulmonary circulation?

heart ←→ lungs

What’s involved in pulmonary circulation?

right ventricle and left atrium

What is systemic circulation?

heart ←→ body

What’s involved in systemic circulation?

right atrium and left ventricle

What are veins?

blood vessels that return blood to the heart

As blood leaves the heart the arteries are rich in oxygen except

for the pulmonary arteries, which carry deoxygenated blood to the lungs.

As blood enters the heart the veins are low in oxygen except

for the pulmonary veins, which carry oxygenated blood from the lungs to the heart.

What is coronary circulation?

Coronary circulation is not the same as systemic circulation in function, though it is technically a specialized part of it. Systemic circulation carries blood to the entire body, while coronary circulation is the dedicated, small-loop system that exclusively supplies oxygenated blood to the heart muscle itself.

What determines the flow of blood?

pressure gradients

valves

What are the two sets of heart valves?

atrioventricular valves

semilunar valves

What are atrioventricular valves?

between the atria and ventricles

What are semilunar valves?

between ventricles and and arteries

What are the types of AV (atrioventricular valves)?

right AV (tricuspid)

left AV (bicuspid or mitral)

What are the types of semilunar valves?

aortic semilunar valve (behind pulmonary valve)

pulmonary semilunar valve

What is a septum?

the heart is divided by this central wall into left and right halves

What is an atrium?

receives blood returning to the heart from the blood vesselse

What is a ventricle?

pumps blood out into the blood vessels

What does the right side of the heart do?

receives blood from the tissues and sends it to the lungs for oxygenation

What does the left side of the heart do?

receives newly oxygenated blood from the lungs and pumps it to tissues throughout the body

What is the flow of blood as it flows through the cardiovascular system?

1. Superior and Inferior Vena Cava: Deoxygenated blood returns from the body.

2. Right Atrium: Receives the deoxygenated blood.

3. Tricuspid Valve: Blood passes from the right atrium to the right ventricle.

4. Right Ventricle: Pumps blood toward the lungs.

5. Pulmonary Valve: Blood enters the pulmonary trunk.

6. Pulmonary Arteries: Carry deoxygenated blood to the lungs.

7. Lungs (Capillaries): Blood becomes oxygenated and releases carbon dioxide.

8. Pulmonary Veins: Carry oxygenated blood back to the heart.

9. Left Atrium: Receives oxygenated blood.

10. Mitral (Bicuspid) Valve: Blood passes from the left atrium to the left ventricle.

11. Left Ventricle: Pumps oxygenated blood to the rest of the body.

12. Aortic Valve: Blood enters the aorta.

13. Aorta: The main artery distributing blood to the body.

14. Systemic Capillaries: Where oxygen and nutrients are delivered to tissues.

15. Superior and Inferior Vena Cava: Deoxygenated blood is collected and returned to the right atrium to begin the cycle again.

What is the superior vena cava?

A large vein that carries deoxygenated blood from the upper body to the right atrium of the heart.

What is the inferior vena cava?

A large vein that carries deoxygenated blood from the lower body to the right atrium of the heart.

What is a portal system?

two capillary beds joined in series

What are the three portal system examples?

digestive tract and liver, joined by the hepatic portal vein

kidneys, where two capillary beds connected in series

hypothalmic-hypophyseal portal system

What heart valves are in contraction?

AV valves close

semilunar valves open

What heart valves are in relaxation?

AV valves open

semilunar valves close

What is the function of the two sets of valves?

prevent the backward flow of blood

What are chordae tendineae?

collagenous cords that prevent the atrioventricular valves from being pushed back into the atria during ventricular contraction

What is the “lub”?

AV valves close at the beginning of ventricular contraction.

What is the “dub”?

Sound produced by the closure of the semilunar valves at the beginning of ventricular diastole.

What does the right side of the heart handle?

low oxygenated blood from body (and pumps to lungs)

What does the left side of the heart handle?

high oxygenated blood from lungs (and pumps to body)

Blood flows from veins into the ___ and from there through one-valves into the ___

atria, ventricles

Blood leaves the heart via the ___ ___ from the right ventricle and via the ___ from the left ventricle. A second set of valves guards the exits of the ventricles so that blood can’t flow back into the heart once it has been ejected.

pulmonary trunk, aorta

In the heart: right atrium

receives blood from → sends blood to

venae cavae to right ventricle

In the heart: right ventricle

receives blood from → sends blood to

right atrium to lungs

In the heart: left atrium

receives blood from → sends blood to

pulmonary veins to left ventricle

In the heart: left ventricle

receives blood from → sends blood to

left atrium to body except for lungs

In the vessels: venae cavae

receives blood from → sends blood to

systemic veins to right atrium

In the vessels: pulmonary trunk (artery)

receives blood from → sends blood to

right ventricle to lungs

In the vessels: pulmonary vein

receives blood from → sends blood to

veins of the lungs to left atrium

In the vessels: aorta

receives blood from → sends blood to

left ventricle to systemic arteries

What parts of body associated with superior vena cava?

arm, head, neck

What parts of body associated with inferior vena cava?

lower body, abdomen, legs

What is the coronary sinus?

It is a vessel that collects deoxygenated blood from the heart muscle and drains into the right atrium.

What is the difference in volume of blood pumped between right and left ventricles?

same volume

Why does the left side of heart has thicker wall?

To pump blood throughout the body, generating higher pressure compared to the right side, which sends blood only to the lungs.

What are papillary muscles?

small muscle in the interior of the ventricles to which the chordae tendineae attach

Trace a drop of blood from the superior vena cava to the aorta, naming all structures the drop encounters along its route.

Superior vena cava → right atrium →

tricuspid (right AV) valve → right ventricle →

pulmonary (right semilunar) valve → pulmonary trunk →

pulmonary arteries → pulmonary capillaries →

pulmonary venules → pulmonary veins →

left atrium → mitral (left AV, bicuspid) valve →

left ventricle → aortic (left semilunar) valve → aorta

What is coronary circulation?

arteries supplying blood to the heart muscle

What are coronary arteries?

arteries supplying blood to the heart muscle

run across the surface of the heart in shallow grooves, branching into smaller and smaller arteries until finally the arterioles disappear into the heart muscle itself

What does red in a diagram mean?

blood is fully oxygenated

What does blue in a diagram mean?

only partially oxygenated blood

What do arteries handle?

blood pumped from the heart

What do veins handle?

send blood back to heart

All arteries are rich in oxygen concentration except

pulmonary arteries

All veins are low in oxygen except for the

pulmonary veins

What is parallel circulation?

A type of blood flow in which blood is distributed to different branches of the circulatory system simultaneously, ensuring that all organs receive oxygenated blood.

advantage: different organs handle blood in specific ways, prevents interference

What is one-way flow?

atria contract together, then the ventricles contract together

What is the function of one-way flow?

heart valves prevent the backward flow of blood

In order to beat the heart needs what three things?

1. rhythm generators, which produce electrical signal

2. conductors to spread the signal

3. contractile cells (cardiac muscle)

What are autorhythmic cells (pacemakers)?

the myocardial cells that signal for myocardial contraction

What are the two types of heart cells?

1. Autorhythmic cells

2. Myocardial cells

How many of the myocardial cells are specialized to generate action potentials?

one percent

How do cardiac and skeletal muscle differ: size?

cardiac muscle fibers are much smaller than skeletal muscle fibers and usually have a single nucleus per fiber

How do cardiac and skeletal muscle differ: neighboring cells?

Individual cardiac muscle cells branch and join neighboring cells end-to-end to create a complex network. The cell junctions, known as intercalated disks, consist of interdigitated membranes.

Intercalated disks have two components: desmosomes and gap junctions. Desmosomes are strong connections that tie adjacent cells together, allowing force created in one cell to be transferred to the adjacent cell

How do cardiac and skeletal muscle differ: connection of cells?

Gap junctions in the intercalated discs electrically connect cardiac muscle cells to one another. They allow waves of depolarization to spread rapidly from cell to cell, so that all the heart muscle cells contract almost simultaneously. In this respect, cardiac muscle resembles single-unit smooth muscle.

How do cardiac and skeletal muscle differ: t-tube?

T-tubes of myocardial cells are larger than those of skeletal muscle, and they branch inside the myocardial cells

How do cardiac and skeletal muscle differ: SR?

Myocardial SR smaller than skeletal muscle, reflecting the fact that cardiac muscle depends in part on extracellular Ca2+ to initiate contraction. In this respect, cardiac muscle resembles smooth muscle.

How do cardiac and skeletal muscle differ: mitochondrion?

Mitochondria occupy 1/3 cell volume of cardiac contractile fiber, a reflection of the high energy demand of these cells

Where does 70-80% of the energy come from in myocardial cells?

circulation

What is the pathway of a signal in autorhythmic cells?

The pathway of a signal in autorhythmic cells begins at the sinoatrial (SA) node, propagates through the atrioventricular (AV) node, leading to coordinated heart contractions.

What is inherent rhythmicity or automaticity?

The ability of heart cells to generate electrical impulses spontaneously, leading to regular heartbeats without external stimulation.

What allows ventricular contraction to squeeze the blood upward from the apex of the heart?

spiral arrangement of ventricular muscle

What do intercalated discs contain?

desmosomes that transfer force from cell to cell, and gap junctions that allow electrical signals to pass rapidly from cell to cell

What is calcium-induced calcium release?

process in which calcium ion entry into a muscle fiber triggers release of additional calcium ions from the sarcoplasmic reticulum

What is pacemaker potential?

autorhythmic cells have unstable membrane potential

cardiac muscle does not rest

What does pacemaker potential contain?

IF channels permeable to K+ and Na+

What are IF channels?

“funny channels”

permeable to K+ and Na+

belongs to the family of HCN channels

What are the steps of action potentials in cardiac muscles?

1. IF channels open

2. some calcium channels open, IF channels close

3. lots of calcium channels open

4. calcium channels close, potassium channels open

5. potassium channels close, IF channels open

What determines the rate at which the heart contracts (heart rate)?

the speed at which pacemaker cells depolarize

What is excitation-contraction coupling?

The physiological process that connects the electrical stimulation of cardiac muscle cells to their contraction, involving calcium release and interaction of actin and myosin.

What are the steps of EC coupling in myocardial cells?

1. action potential enters from adjacent cell

2. Voltage-gated calcium channels open; calcium enters cell

3. calcium-induced calcium release through ryanodine receptor-channels (RyR)

4. local release causes calcium spark

5. summed calcium sparks create calcium signal

6. calcium ions bind to troponin to initiate contraction

7. relaxation occurs when calcium unbinds from troponin

8. calcium is pumped back into the SR for storage

9. caclium is exchanged with sodium through NCX antiporter

10. sodium gradient is maintained by the sodium-calcium ATPase

What is the RyR?

ryanodine receptor calcium ion

release channels in cardiac muscle that mediate calcium-induced calcium release

What is the sodium-calcium exchanger (NCX)?

A membrane protein that facilitates the exchange of sodium ions for calcium ions across the cell membrane, crucial for calcium homeostasis in cardiac cells.

What kind of transport is “calcium is exchanged with sodium by NCX“ in EC coupling in cardiac muscle?

Secondary active transport, specifically antiport.

What kind of transport is “sodium gradient is maintained by the Na-K ATPase“ in EC coupling in cardiac muscle?

primary active transport