Circulatory System

Question 1

Heart Sounds

Answer 1

“Lubb” - tricuspid and bicuspid valves closing

“Dupp” - semilunar valves closing

Question 2

Inflammatory Response

Answer 2

1. Mast cells release histamine and heparin into intercellular fluid
2. Histamine increases blood flow and increases capillary permeability
3. Heparin prevents clotting
4. Heat, redness and swelling
5. Phagocytes clear debris
6. Pain receptors are triggered

Question 3

The Cardiac Cycle

Answer 3

1. Atrial and ventricular diastole
2. Atrial systole
3. Ventricular systole

Question 4

Pathogens

Answer 4

Microbes capable of causing disease

• bacteria
• viruses
• fungi
• parasites

Question 5

Blood pressure

Answer 5

The force with which the fluid in the vessels pushes on the vessels wall

Question 6

First line of defense

Answer 6

skin; impervious barrier
mucous; traps pathogens
secretion; acidity inhibits entrance

Question 7

Stroke volume

Answer 7

volume of blood forced from ventricle with each contration

Question 8

Cardiac output

Answer 8

the amount of blood leaving the ventricles at a time

Question 9

Vasoconstriction

Answer 9

muscle in the artery constricting to reduce blood flow

Question 10

Vasodilation

Answer 10

widening of the arteries to increase blood flow

Question 11

Elements of heart rate control

Answer 11

Adrenaline, medulla, sino-atrial node, atrio-ventricular node

Question 12

Adrenaline

Answer 12

A hormone that increase the rate and force of heart beats

Causes vasodilation of skeletal muscles and vasoconstriction of peripheral and organ blood vessels

Question 13

Medulla

Answer 13

Controls the cardiac centre and vasomotor centre parts of the brain

Question 14

Cardiac centre

Answer 14

relays messages to the SA node and manages the speed of the heart

Question 15

Vasomotor centre

Answer 15

Controls vasodilation and vasoconstriction

Question 16

Sino-atrial node

Answer 16

Rhythmically causes depolarisation of neurons causing atrial systole
Also relays info to the A/V node

Question 17

Atrio-ventricular node

Answer 17

Produces depolarisation of neurons causing ventricular systole

Question 18

Blood Components

Answer 18

All produced by red bone marrow
Plasma - water, Na+, Ca+, amino acids, hormones, urea
Erythrocytes - 5 mill per ml, survives for 120 days
Leucocytes - 6000-7000 per ml, protects body from pathogens
Thrombocytes - only lasts a week (platelets)

Question 19

Oxygen transport

Answer 19

Blood with high conc of oxyhaemoglobin is found in the arteries (not around the lungs)
RBC transport oxyhaemoglobin; contains haemoglobin, no nucleus, biconcave discs
Blood with low conc of oxyhaemoglobin in found in the veins

Question 20

Carbon Transport

Answer 20

8% dissolved in plasma
70% bicarbonate ions
22% carbominohaemoglobin

Question 21

Coagulation

Answer 21

Damaged cells of blood vessels release adenosine diphosphate - attracts platelets
Grouped platelets form platelet plug
Platelets contact exposed collagen; release more ADP, serotonin and platelet factors
Thrombin converts fibrinogen to fibrin (insoluble)
Fibrin forms a clot

Question 22

Intracellular fluid

Answer 22

Fluid inside the cells

64% of fluid in blood

Question 23

Intercellular fluid

Answer 23

Fluid between the cells

Excess is collected by lymph vessels

Question 24

Extracellular fluid

Answer 24

Outside of the cells

eg plasma

Question 25

Lymph nodes

Answer 25

Site of filtration

Located along the length of the lymph vessels

Question 26

Phagocytosis

Answer 26

Macrophages engulf particle, surrounds the particle with projections which force the particle into the microphages, and the particle is digested in 10-30mins

Question 27

Inflammatory response

Answer 27

1.

Question 28

Lymphatic System

Answer 28

Blind ended tubules that collect excess intercellular fluid and prevent the spread of pathogens through filtration
Lymph is filtered by lymph nodes
Rejoins the blood stream at the vena cava