3.2 transport in animals

Question 1

what is the structure of arteries?

Answer 1

• very narrow lumen
• thick smooth muscle
• collagen
• connective tissue
• elastic fibres

Question 2

what is the structure of arterioles?

Answer 2

• smooth muscle
• narrow lumen
• endothelium
• connective tissue

Question 3

what is the structure of capillaries?

Answer 3

• narrow lumen
• one cell thick endothelium
• small leaky gaps

Question 4

what is the structure of veins?

Answer 4

• very large lumen
• smooth muscle
• thin walls
• valves
• endothelium
• collagen
• elastic fibres

Question 5

what is the strucutre of venules?

Answer 5

• large lumen
• smooth muscle
• thin walls
• porous
• squamous epithelial cells
• collagen
• poorly developed elastic fibres

Question 6

what are the 3 components of blood vessels?

Answer 6

• tunica externa
• tunica media
• tunica intima

Question 7

what are the changes in pH in red blood cells?

Answer 7

CO2 diffuses into red blood cell and forms carbonic acids, which dissociates releasing H+ ions, this decreases the pH and affinity for oxygen. So oxyhaemoglobin releases O2 to the respiring tissues

Question 8

At the lungs:

Answer 8

• low pCO2
• curve moves to the left
• increase O2 affinity
• increased O2 loading

Question 9

at the tissues:

Answer 9

• high pCO2
• curve moves to the right
• decreased O2 affinity
• increased release of O2

Question 10

what is the Bohr effect?

Answer 10

The Bohr effect refers to shifts to the oxyhaemoglobin dissociation curve. An increase in partial pressure of carbon dioxide will shift the S-curve to the right, whereas a decrease in partial pressure of carbon dioxide shifts the curve to the left.

Question 11

Foetal haemoglobin:

Answer 11

• high affinity for oxygen than adult haemoglobin

Question 12

Describe the transport of CO2 in red blood cells

Answer 12

1. CO2 diffuses into RBC
2. CO2 is converted into carbonic acid by carbonic anhydrase
3. carbonic acid dissociates to form hydrpgen and hydrogen carbpnate ions
4. hydrogen carbonate ions diffuse out of the RBC and combine with sodium ions in the plasma to form sodium hydrogencarbonate
5. the HCO3- ions are replaced with chlorid ions
6. H+ ions combine with haemoglobin to form haemoglobinic acid
7. oxyhaemoglobin dissociates due to low pO2 so oxygen is released into the blood plasma

Question 13

what are the 3 forms that CO2 is transported in?

Answer 13

• dissolved CO2 in the plasma
• hydrogen carbonate ions
• combined directly with haemoglobin

Question 14

how is oxygen transported?

Answer 14

In the lungs, O2 binds to the iron in the haemoglobin to form oxyhaemoglobin.

Question 15

describe the structure of haemoglobin

Answer 15

• large protein molecule
• 4 polypeptide chains each with and iron containing haem group

Question 16

What does the p-wave on an ECG show?

Answer 16

atrial stimulation caused by the depolarisation of the atria

Question 17

What does the t-wave on an ECG show?

Answer 17

Diastole caused by the repolarisation of the ventricles

Question 18

What does the QRS complex on an ECG show?

Answer 18

atrial systole caused by the depolarisation of the heart

Question 19

heart rate equation

Answer 19

heart rate = 60 / time take for 1 heart beat

Question 20

cardiac output equation

Answer 20

cardiac output = stroke volume X heart rate

Question 21

what is atrial fibrillation?

Answer 21

• irregular heart beat as the atria or ventricles lose thier rhythm.
• the p-waves on an ECG are unclear

Question 22

what is an ectopic heartbeat?

Answer 22

when the heart beats too early

Question 23

what is bradycardia?

Answer 23

when the heart is beating too slowly

Question 24

what is tachycardia

Answer 24

when the heart is beating too fast

Question 25

what is the sino-atrial node?

Answer 25

a small patch of tissue that acts as a pacemaker, it initiates a wave of excitation at regular intervals

Question 26

what are the 4 main parts involved in the control of the heart beat?

Answer 26

• sino atrial node
• atrioventricular node
• bundle of his
• purkinje fibres

Question 27

what is the autonomic nervous system?

Answer 27

the part of the nervous system that controls involuntary action

Question 28

why is the cardiac muscle myogenic?

Answer 28

the muscle can contract without stimulation from outside nerves

Question 29

describe the pathway of electrical activity in the heart

Answer 29

1. the sino atrial node initiates a wave of excitation that spreads pver the walls of the atria causing them to contract
2. the atrioventricular node delays the wave of excitation, allowing the atria to empty
3. the wave travels down the bundle of His and purkinje fibres, causing the ventricles to contract from the apex upwards

Question 30

what happens if the coronary arteries become blocked?

Answer 30

blood flow will be restricted

• angina
• myocardia infarction

Question 31

what are coronary arteries?

Answer 31

the arteries that supply oxygenated blood to the cardiac muscle

Question 32

what is the septum?

Answer 32

a wall of muscle that separates the left and right sides of the heart

Question 33

what are tendinous cords?

Answer 33

they are attacthed to the vavles, preventing them from turing inside out

Question 34

what are red blood cells called?

Answer 34

erythrocytes

Question 35

what are white blood cells called?

Answer 35

leukocytes

Question 36

what are platelets?

Answer 36

cell fragments that are important in the clotting process

Question 37

what is plasma?

Answer 37

a liquid medium that trasports dissolved substances
e.g.
- O2
- CO2
- glucose
- amino acids

Question 38

what is tissue fluid?

Answer 38

a fluid surround the cells in a tissue, it doesnt contain plasm proteins

Question 39

what is lymph?

Answer 39

the remaining 10% of tissue fluid that isnt returned to the capillaries, instead it is reurned to the blood stream via the lymphatic system

Question 40

how is tissue fluid formed?

Answer 40

Tissue fluid is formed at the arteriole end of the capillary where there is large hydrostatic pressure from the left ventricle of the heart. This hydrostatic pressure within the capillary is greater than the pressure in the fluid surrounding the capillaries, therefore forcing the fluid out of the capillaries.

Question 41

what is hydrostatic pressure?

Answer 41

the pressure that a fluid exerts when pushing against the sides of a vessel

Question 42

what is oncotic pressure?

Answer 42

the pressure created by the osmotic effects of solutes

Question 43

what is cardiac output?

Answer 43

the volume of blood pumped by the heart in 1 minute

Question 44

what is the role of the heart?

Answer 44

to create pressure that pushes blood around the blood vessels

Question 45

what is atrial systole?

Answer 45

the contraction of the atria, pushing blood into the ventricles

Question 46

what is diastole?

Answer 46

the relaxation of the muscular walls of all 4 chambers of the heart

Question 47

what is ventricular systole?

Answer 47

the ventricles contract from the apex upwards forcing blood out of the heart

Question 48

why is the left ventricle thicker than the right?

Answer 48

to maintain a higher pressure so that the blood can reach the whole body, overcoming the resistance of systemic circulation