Circulatory systems in animals and the heart

Question 1

What are the 4 main types of blood vessels?

Answer 1

arteries, arterioles, capillaries, and veins.

Question 2

what is the function of the arterioles?

Answer 2

They transport blood from the arteries, to the capillaries.

Question 3

What structures do all blood vessels contain? In order.

Answer 3

Outer layer, muscle layer, elastic layer, lining layer, lumen.

Question 4

describe the structure of the arteries, and relate this to its function.

Answer 4

Thick muscle layer, which contracts and relaxes, in order to control blood flow.
Thick elastic layer, that strectches and. recoils, in order to maintain high blood pressure.
The outer layer is very thivk, in order to prevent the artery from bursting, due to high pressure.

Question 5

Describe the structure of arterioles, and relate this to its function.

Answer 5

Have the thickest muscle layer, which contracts in order to reduce blood flow to capillaries.
Thin elastic layer, as they dont need to maintain a high blood pressure

Question 6

desribe the structure of the veins, and relate this to its function.

Answer 6

Veins have a relative thin muscle wall, because blood flow doesnt need to be controlled.
Thin elastic layer, as only low blood pressure is needed.
outer layer is thin.
They also contain valves, in order to preven blood from flowing backwards.

Question 7

describe the structure of capillaries.

Answer 7

They have a lumen, and a lining layer.

Question 8

descrobe the adaptations a capillary has in order to improve its function.

Answer 8

Thin lining layer, and narrow lumen, in order to provide a shorter diffusion pathway.

Capillaries are numerous and branched, which provide a large surface area for exchange.

Question 9

what is the circulatory system?

Answer 9

Blood vessels connect to organs, in order to form the circulatory system.

Question 10

describe how arteries and veins carry blood.

Answer 10

Arteries carry blood away from the heart.
Veins carry blood towards the heart.

Question 11

describe all the arteries that carry blood away from the heart.

Answer 11

pulmonary artery ( to the lung), Aorta ( To the renal artery), renal artery ( to the kidneys).

Question 12

describe all the veins that carry blood towards the heart.

Answer 12

renal vein ( to vena cava), Vena cava (To the heart), pulmonary vein ( to the heart).

Question 13

Describe the pathway of blood. ( state wether it is oxygenated or deoxygenated).

Answer 13

Heart , pulmonary artery , pulmonary vein , aorta , renal artery , renal vein, vena cava, heart.

( THIS REPEATS).

Question 14

What is tissue fluid? describe its structure and its function.

Answer 14

Tissue fluid, is a liquid sorrounding cells.
It contains a range of substances, including glucose, water and ions ( formed fom plasma).
It controls the exchange of substances between the blood and the cells.

Question 15

explain how tissue fluid is formed, and how it returns to the capillaries.

Answer 15

Blood moving into the capillaries, has a high hydrostatic pressure.

Thismhigh hydrostatic pressure forces water, along with small dissolved substances, out of the capillaries, thus forming tissue fluid.

the loss of fluid, and removal of plasma proteins, reduces the water potential, and hydrostatic pressure, at the venus end of the capilary.

This allows fluid to be returned to the blood, as a result of osmosis, and external high hydrostatic pressure.

Question 16

In which other way, does a small percentage of tissue fluid, return to the blood plasma.

Answer 16

through the lymphatic system.

Question 17

Describe the structure of the human heart.

Answer 17

CHECK IMAGE ON ONE NOTE.

Question 18

what is the function of the coronary arteries?

Answer 18

To supply the heart muscles with blood, which contains oxygen.

Question 19

what happens if there is a blockage in the coronary arteries?

Answer 19

It may lead to a shortage of blood to the heart.
This means that the muscle cells ( in the heart), cant get any oxygen, which means that they cant respire, and thus, will die.

This disease is known as Myocardial infarction.

Question 20

what increases the chances of myocardial infarction?

Answer 20

smoking, and high blood pressure.

Question 21

what is the heart cycle?

Answer 21

Sequence of events, that the heart undergoes, in order to pump blood around the body.

Question 22

Describe the first step of the cardiac cycle.

Answer 22

ATRIVENTRICULAR DISTOLE:
The atria and ventricles relax.
When the blood pressure in the atria, is greater than the blood pressure in the ventricles, is greather than that in the ventricles, the atrioventricular valves, open.

Question 23

Describe the second step of the cardiac cycle.

Answer 23

The atria contract, and the ventricles relax.
This decreases the volume in the atria, thus increasing the pressure.
The remaining blood, enters the ventricles.

Question 24

Describe the third step of the cardiac cycle.

Answer 24

The ventricles contract ( the atria relax).
When the pressure of the ventricles, is greater than the pressure of the atria, the atriventricular valves close, thus preventing the backwords flow of blood, into the atria.
Meanwhile, the semilunar valves are opened, which causes the blood to move inside the vessels.

When the pressure inside the blood vessels is greater than the ventricular pressure, the semilunar valves shut, thus preventing the backwords flow of blood , into the heart.

Question 25

What is cardiac output, and what is the formula for it?

Answer 25

Cardiac output is the volume of blood, pumped by a ventricle, in one minute.

formula: stroke volume X heart rate.

stroke volume: volume of blood, pumped out at each beat.