Cardiovasc system

Question 1

Arteries

Answer 1

-Carry blood away from heart under high pressure
-Transport oxygenated blood (except pulmonary)
-No valves
-Reddish colour
-Thicker walls than veins

Question 2

Veins

Answer 2

-Carry blood towards heart under low pressure
-Transport deoxygenated blood (except pulmonary)
-May contain valves to prevent backflow
-Blueish colour
-Thinner walls than arteries

Question 3

Capillaries

Answer 3

-Between arterioles and venules
-Only 1 layer (tunica intima)

Question 4

Vein and artery walls

Answer 4

Tunica intima, Tunica media and tunica adventitia are the 3 layers

Question 5

Blood composition

Answer 5

Plasma - contains nutrients/waste/antibodies
Plasma proteins - Albumin maintains osmotic concentration and fibrinogen and prothrombin form blood clots.

Question 6

Blood functions

Answer 6

1. Transport gases to/from body and lungs
2. Transport nutrients
3. Transport waste products to liver/kidney
4. Regulates body fluid volume
5. Defends against infection
6. Regulates body temperature by conducting heat

Question 7

How are erythrocytes formed

Answer 7

Formed by erythropoiesis in bone marrow, which takes 4-7 days. Production is controlled by Erythropoietin.

Question 8

Erythrocyte function

Answer 8

Transports oxygen and some CO2

Question 9

Leucocytes function

Answer 9

-Defend the body against infections
-Have nuclei

Question 10

Granulocytes types (leucocytes)

Answer 10

-Basophils secrete histamine
-Neutrophils phagocytose bacteria
-Eosinophils are involved in allergic responses

Question 11

Agranulocyte types (leucocytes)

Answer 11

-Lymphocytes produce antibodies (B)
-Monocytes transform into macrophages

Question 12

How are thrombocytes/platelets formed

Answer 12

-Formed from megakaryocytes in bone marrow

Question 13

Thrombocytes function

Answer 13

-Blood clotting

Question 14

How does blood clotting work?

Answer 14

1. Platelets stick to damaged blood vessel and release THROMBOPLASTIN.
2. This converts PROTHROMBIN TO THROMBIN
3. THROMBIN converts FIBRINOGEN to FIBRIN to make a clot.
   -Clotting time is increased by lack of vit K and decreased by raised temperatures.

Question 15

What is a thrombus

Answer 15

A blood clot blocking a vein/artery.

Question 16

What artery and vein is in the forelimbs

Answer 16

Brachial

Question 17

what is a hepatic portal system

Answer 17

A circulation system that directs blood from the digestive tract to the liver

Question 18

Where would you take blood from a cat

Answer 18

External jugular vein, Cephalic vein and femoral vein.

Question 19

Where would you take blood from a dog

Answer 19

External jugular vein, Cephalic vein and Saphenous vein.

Question 20

Where would you find a cows pulse

Answer 20

Facial artery near the jaw, or Coccygeal artery at the tail base.

Question 21

What is the Mediastinum

Answer 21

The central compartment of the thoracic cavity where the heart is located.

Question 22

What is pericardium

Answer 22

Double layered (parietal and viscous layers) sac that encloses the heart

Question 23

What are the three heart muscle layers

Answer 23

1. Endocardium - inner layer
2. Myocardium - middle composed of cardiac muscle
3. Epicardium - outer layer that forms inner pericardium layer.

Question 24

What is so good about cardiac muscle

Answer 24

It can continuously contract with minimal fatigue.

Question 25

What do valves do in the heart

Answer 25

They prevent backflow -Atrioventricular close during ventricular contraction -Semilunar close after ventricular contraction.

Question 26

Explain the steps of the Cardiac cycle

Answer 26

1. Atrial Diastole (relaxation): blood fills atria and is passed to ventricles 2. Atrial Systole (contraction): blood is forced into ventricles by contractions. 3. Ventricular Diastole: Ventricles fill slowly and AV valves close. 4. Ventricular Systole: Blood is ejected into the aorta and pulmonary trunk and SL valves close.

Question 27

What is blood pressure

Answer 27

The force of blood against artery walls. (systolic or diastolic when heart contracts or relaxes)

Question 28

What are some features of the Immune system

Answer 28

-Skin is a physical barrier against pathogens -Spleen is involved in filtering blood -Sweat inhibits bacterial growth

Question 29

What is the innate immune system

Answer 29

-Fast non specific responses to organisms -present at birth

Question 30

What is the Adaptive immune system

Answer 30

-Slower responses to specific organisms -Uses antibodies and memory cells

Question 31

Conduction System

Answer 31

1. SA node initiates contraction which spreads across both the atria (ATRIAL SYSTOLE) 2. The nerve impulse must pass through the AV node at the top of the septum. 3. The AV node sends impulses to the Bundle of His, which runs down the intraventricular septum. 4. The Bundle of His divides into branches in the ventricles, and these connect with neurons called Purkinje fibres (in ventricular muscle) 5. A wave of contraction starts in the myocardium at the apex, and spreads up through ventricular muscles, pushing blood to the oulmonary artery and aorta.