Human Physiology: Blood System

Question 1

Define systole

Question 2

Define dystole

Question 3

Define double and closed circulatory system

Question 4

Name the vessel

1. Brain to heart, heart to brain
2. Kidney to heart, heart to Kidney
3. Liver to heart, and back
4. Leg to heart, and back
5. Stomach to liver
6. Arms to heart, and back
7. Stomach to heart, and back

Answer 4

1
2
3
4
5
6
7

Question 5

Explain the structural Adaptations of arteries to its function

Answer 5

Have thick walls - to withstand the high pressure from the heart
Have narrow lumen-to maintain high blood pressure
Carry blood under high pressure
Elastic and muscular inner wall- to help maintain a pulse flow

Question 6

Characteristics of veins

Answer 6

Wide lumen
Thin walls
Presence of valves - prevent the back flow of blood

Question 7

Explain the Structural Adaptations of the heart to its function

Answer 7

Has myogenic muscles
Divided into two by antrio ventricular septum, to prevent mixing of oxygenated and deoxygenated blood.
The cardiac has numerous mitochondria which generate energy that enable the heart to contract and relax without fatigue
Has specialised cell muscles that spontaneously initiate and maintain contraction of the heart

Question 8

Explain vasoconstriction

Question 9

Explain vasodilation

Question 10

Characteristics of capillaries

Answer 10

Capillaries provide the exchange surface in the tissues of the body through capillary beds

Walls made of a single layer of endothelial cells ,reducing the diffusion distance for O and CO2 btn the blood and the tissue of the body.
pores btn endothelium cells which allow blood plasma to leak out and form tissue fluid.
Extremely narrow lumen that forces blood to flow slowly, providing more opportunity for diffusion to occur
Capillary beds(branches) increase the SA for diffusion of substances to and from cells , being so close to the cells also reduces the diffusion distance.

Question 11

Define sinoatrial node (SAN)?

Question 12

Describe how SAN intiates heartbeat?

Answer 12

Depolarisation of the cells in San sends an electrical signal over the atria, causing then to contract in atrial systole
This impulse stimulates antrioventrucular node
Avn sends signals down the septum via the bundle of his
The bundle of his innervates purkinje fibres in the ventricular wall, causing ventricular contraction.

Question 13

Low blood pressure, low oxygen concentration, and low pH suggests that?

Answer 13

that the heart rate needs to speed up, to increase the flow rate of blood to tissues , deliver more oxygen and remove more co2

Question 14

High blood pressure, high oxygen concentration and high pH suggests that?

Answer 14

High blood pressure, high oxygen concentration and high pH are all indicators that the heart rate may need to slow down.

Question 15

Function of Hormone Epinephrine/adrenaline

Answer 15

Hormone Epinephrine/adrenaline increase the heart rate to prepare for vigorous physical activity. Boosts the delivery of oxygen and glucose to brain and muscles.

Question 16

How does coronary occlusion/ atherosclerosis occur

Answer 16

Atheromas (fatty acids) develop in arteries reducing the diameter of the lumen
The restricted blood flow increases pressure in artery, damaging the arterial wall
As the lining is progressively degraded,plaques form
If the plaque raptures, blood clotting is triggered,forming a thrombus that restricts a blood flow.
If the thrombus is dislodged it becomes an embolus and can cause a blockage