BIOC34H3 Lecture Notes - Lecture 1: Third-Degree Atrioventricular Block, Interventricular Septum, Ectopic Pacemaker

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4 Jan 2018

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Left ventricle muscles are much thicker than the right for the following reasons: It pumps blood out to a high-pressure system (systemic circulation: higher resistance (resistance of blood flow), more thickness of muscles, increased force needed to pump out the blood. Right ventricles do not the muscles to be as thick b/c they send their blood to the lungs, experience less resistance and require less force to pump out the blood. Arteries: carry deoxygenated blood going to the lungs (away from heart) Veins: carry oxygenated blood going to the heart from the lungs. Atria and ventricles separated by septa i. e. interatrial septum separates the atria, and interventricular septum separates two ventricles. Steps 1-2 = very rapid; cells are large; little resistance to current flow. Step 3 = current slows down; resistance increases; av node cells are small. The slowing down is an important step atria finishes contracting before the ventricles contract.

Related Questions

Match the part of the human heart with its function

	Right ventricle
	Left atrium
	Left ventricle
	Aorta
	Pulmonary artery
	Vena
	Pulmonary veins

A.	Receives blood from the vena cava, delivers blood to the right ventricle.
B.	Blood enters this chamber via the right atrioventricular valve, delivers oxygen-poor blood to the lungs.
C.	Receives oxygen rich blood from the lungs, delivers blood immediately through the left atrioventricular valve.
D.	Receives blood from the left atium, delivers blood to the body via the aorta.
E.	Largest artery in the body.
F.	Delivers blood to the lungs from the right ventricle.
G.	There are actually two of these veins, superior and inferior.
H.	These veins have the highest concentration of oxygen in them and deliver blood back to the heart from the lungs.

tealhyena132

1. Which of the following is the correct sequence of bloodflow?

a. heart --> atery --> arteriole --> capillary -->vein --> venule --> heart

b. heart --> vein --> venule --> capillary -->arteriole --> artery --> heart

c. heart --> artery --> arteriole --> capillary -->venule --> vein --> heart

d. heart --> artery --> venule --> capillary -->arteriole --> vein --> heart

e. heart--> artery --> capillary --> arteriole -->venule --> vein --> heart

2. What are the functions of the elastic fibers that are foundin the walls of ateries? (there may be more than one answer)

Select one or more:

a. they allow the artery to stretch and then recoil back to itsoriginal shape as blood is forcegully pumped from the heart intothe arteries

b. they allow arteries to lengthen as the volume of blood in thearteries increase

c. they help maintain a steady blood pressure during thedifferent phases of heart contraction

d. they smooth out the walls of the arteries to preventturbulent blood flow

3. Which of the following are functions of the lymphatic system?(there may be more than one answer)

Select one or more:

a. help fight infections and cancer

b. allows excess interstitial fluid (fluid found between thecells in your tissues) to get dumped back into your blood

c. brings large molecules from fat digestion into thebloodstream so that they can be processed and stored

d. all of the above are functions of the lymphatic system

4. Which of the following blood vessels bring newly oxygenatedblood from the blood vessels in the lungs back to the heart so thatthe heart can pump it to the rest of the body?

Select one:

a. aorta

b. inferior vena cava

c. pulmonary vein

d. pulmonary artery

5. Which of the following mechanisms help blood fight gravity sothat, for instance, it can return from blood vessels in your feetback into your heart? (there may be more than one answer)

Select one or more:

a. breathing allows the pressure in your chest to decrease andallow blood to flow up towards your heart

b. as you walk, the skeletal muscles in your legs contract andsqueeze the veins; since veins have valves, blood flows up anddoesn't backflow back down

c. the force of blood flowing out of the heart and into thearteries pushes all of the blood along, causing blood to return tothe heart

d. precapillary sphincters open to allow blood to flow backtowards the heart

6. The tricuspid and bicuspid/mitral valves prevent backflow ofblood from the atria into the ventricles.

Select one:

True

False

7. The following sequence represents the correct order of bloodflow through the heart:

inferior and superior vena cava --> right atrium --> rightventricle --> pulmonary artery --> lungs --> pulmonaryvein --> left atrium --> left ventricle --> aorta

Select one:

True

False

8. Capillaries are as wide as one red blood cell.

Select one:

True

False

9. The purpose of the coronary arteries is to bring oxygenatedblood to the walls of the heart so that the muscles in the heartwalls can contract.

Select one:

True

False

10. Vasodilation refers to the narrowing of blood vessels.

Select one:

True

False

ultramarinealligator67

1) The external layer of the heart wall is the

Multiple Choice

endocardium.

myocardium.

epicardium.

parietal pericardium.

2) Check all that are characteristics of cardiac muscle.

Check All That Apply

Cells are long and cylindrical.

Cells are short and branching.

Cells have multiple nuclei at the periphery of the cell.

Cells have one or two nuclei in the center of the cell.

They are composed of thick and thin filaments.

The functional contractile unit is the sarcomere.

3) Match the chamber of the heart with the structure(s) from which it receives blood.

Coronary sinus

Pulmonary veins

Right atrium

Left atrium

Match each of the options above to the items below.

Right atrium

Right atrium Open choices for matching

Right ventricle

Right ventricle Open choices for matching

Left atrium

Left atrium Open choices for matching

Left ventricle

4) The less extensive distribution of T-tubules contributes to the more delayed onset and prolonged contraction of cardiac muscle tissue compared to skeletal muscle tissue.

True or False

5) The cells of the ___________ act as the heart's pacemaker, which establishes the pace for cardiac activity.

Multiple Choice

atrioventricular (AV) node

sinoatrial (SA) node

atrioventricular (AV) bundle

Purkinje cells

6) Match the cardiac vein with its description.

Travels close to the right marginal artery

In posterior interventricular sulcus

In anterior interventricular sulcus

In the posterior portion of cornary sulcus

Match each of the options above to the items below.

Great cardiac vein

Great cardiac vein Open choices for matching

Middle cardiac vein

Middle cardiac vein Open choices for matching

Small cardiac vein

Small cardiac vein Open choices for matching

Coronary sinus

7) Parasympathetic innervation to the heart comes from the medulla oblongata via the left and right ___________ nerves.

8) Check all that are components of the sympathetic innervation of the heart.

Check All That Apply

Cervical sympathetic ganglionCervical sympathetic ganglion

Spinal cordSpinal cord

Vagus nerve (CN X)Vagus nerve (CN X)

Cardiac nerveCardiac nerve

Sympathetic postganglionic axon

9) Check all that occur during ventricular contraction.

Check All That Apply

The AV valves open to allow blood to enter the ventricles from the atria.The AV valves open to allow blood to enter the ventricles from the atria.

The semilunar valves remain closed to prevent backflow of blood into the ventricles.The semilunar valves remain closed to prevent backflow of blood into the ventricles.

The semilunar valves open to allow blood to flow into the large arteries.The semilunar valves open to allow blood to flow into the large arteries.

The AV valves close to prevent backflow of blood into the atria.

BIOC34H3 Lecture Notes - Lecture 1: Third-Degree Atrioventricular Block, Interventricular Septum, Ectopic Pacemaker

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