Module 4 - Circulation and Gas Exchange Flashcards Preview

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Flashcards in Module 4 - Circulation and Gas Exchange Deck (63):
1

What kind of diffusion occur across the respiratory surface?

Passive diffusion.

2

What features must the respiratory surface have?

Respiratory surface must have large surface area and a thin membrane.

3

What does oxygen need to do before it can diffuse?

Oxygen needs to dissolve in fluid before it can diffuse.

4

What is partial pressure?

PP - the pressure exerted by a particular gas in a mixture of gases.

5

What is Henry's Law?

the solubility of gas in liquid is directly proportional to the partial pressure of that gas in equilibrium with the liquid

6

What type of exchange occurs in gills? Explain

Countercurrent exchange - this is where the water flows through gill filaments in the opposite direction of the blood flowing through the capillaries in the gill filaments. The pp of oxygen in water decreases as it flows through the gill filaments, and the pp of oxygen in blood being highest where the water first crosses.

Water: 150 120 90 60 30 (flowing left to right)
Blood: 140 110 80 50 20 (flowing right to left)

7

4 facts about tracheal systems

- exist in insects
- no link between gases and blood
- oxygen goes directly to cells
- moisture is easily lost as the size of the tracheole decreases

8

How many alveoli do humans have and what surface area does this create?

300 million alveoli gives 80 to 100 square metres

9

Pulmonary vs systematic circulation

Pulmonary
- heart and lungs
- deoxygenated blood to lungs - oxygenation - oxygenated blood returns to the heart
- low pressure system
- removes CO2 from blood and adds O2

Systematic
- heart and rest of the body
- oxygenated blood to the body - deoxygenation - deoxygenated blood returns to the heart
- high pressure system
- provides body cells with O2 and removes CO2

10

Positive vs negative pressure breathing

Positive
- inhaled air closed into nasal cavity, air rushes into lungs as pressure is lower there (push air into lungs).

Negative
- expansion of lungs reduces pressure, so air rushes into lungs (suck air in)
- exhalation by relaxation of diaphragm and rib muscles, decreases lung volume and air moves out of lungs

11

What is the change in volume in negative pressure breathing in humans?

Very small: 3-4 mmHg

12

Roles of preural sac

- forms a fluid filled double membrane surrounding the lung
- keeps lungs stretched and attached to ribs

13

What is the residual volume?

bottom 1200mL, always in the lungs, the volume of air remaining in the lungs after a maximal expiratory effort.

14

What is the expiratory reserve volume?

1100ml on top of residual volume, the max that can be exhaled after normal expiration

15

What is the funtioncal residual capacity?

residual + expiratory reserve = bottom 2300mL, the volume of air at the end of passive expiration.

16

What is the tidal volume?

500mL above functional residual capacity - the difference of volumes after normal inhalation and exhalation

17

What is the inspiratory reserve volume?

3000mL above tidal, the max that can be inhaled after normal inhalation

18

What is the insiratory capacity?

tidal plus inspiratory reserve - the max inhaltion after normal expiration

19

What is the vital capacity?


4600mL - that is total lung capacity minus the residual volume, the greatest volume of air that can be expelled from the lungs after taking the deepest possible breath.

20

What is the total lung capacity?

5800mL

21

What are the responses to an increase in CO2 concentration in the blood?

- decreased pH
- increased rate and depth of ventilation

22

Partial pressures in mmHg of O2 and CO2 in 6 phases of respiration

Inhaled air - 160 O2, 0.2 CO2
Alveolar spaces - 104 O2, 40 CO2
Pulmonary veins and systemic arteries - 104 O2, 40 CO2
Body tissue - 45 CO2
Pulmonary arteries and systemic veins - 40 O2, 45 CO2
Exhaled air - 120 O2, 27 CO2

23

Features of haemoglobin

- 4 polypeptide chains
- 4 Heme groups with iron atom
- can carry 4 oxygen molecules each
- as the number of oxygen molecules that are already bound increases, the ease of binding another O2 increases too (works in reverse too with unloading)
- first on or first off is the hardest

24

Partial pressure of O2 and subsequent O2 saturation of hemoglobin in:
- tissues during exercise
- tissues at rest
- the lungs

What does this imply?

Lungs
pp O2 = 100%
sat = 100%

Tissues at rest
pp O2 = 40%
sat = 70%
30% oxygen offloaded to tissues

Tissues during exercise
pp O2 = 10 - 15%
sat = 80% oxygen offloaded to tissues

25

What does a decrease in pH imply for haemoglobin?

Hemoglobin retains less O2 at a lower pH, so at the same partial pressure, the O2 saturation of hemoglobin is less when pH is lower.

26

What occurs to diffusion as the size of an animals increases? How is this overcome?

Diffusion becomes inefficient as the time it takes for O2 to diffuse is proportional to the square of the distance it diffuses.
Circulatory systems overcome this.

27

Open vs closed circulatory systems

Open
- blood is pushed down between organs into the haemolymph in the sinuses (the gaps)
- CO2 waits in the sinuses and is picked up by the blood there
- O2 delivered to sinuses and picked up by cells from there
- tubular heart
- insects
- one fluid
- simple, easy to maintain
- less energy and less pressure

Closed
- 2 fluids - interstitial (around and between organs) and blood
- blood never leaves circulatory systems
- diffusion of gases across blood vessel membranes to interstitial fluid and back
- higher pressure, results in increased efficiency for meeting high metabolic demand

28

Single vs double (amphibian) vs double (mammal) circulation

Single
- 1 circuit
- fish
- blood from heart to gills to body to heart

Double
- 2 circuits: one to lungs and one to body
In amphibians
- some mixing of blood as there is only one ventricle
- pulmocutaneous circuit includes lungs and skin capillaries

In mammals
- no mixing of blood at all as circuits are kept seperate by 2 ventricles

29

2 heart value types and location

Atrioventricular (AV) values - between atria and ventricles

Semilunar values - between ventricles and arteries (aorta and pulmonary artery)

30

Where are bicuspid and tricuspid values found?

Bicuspid - left
Tricuspid - right

31

Systole vs diastole

systole - contraction/pumping
diastole - relaxation/filling

32

What is cardiac output?

Heart rate (beats per min) x stroke volume (L per beat) = L/ per min

33

3 muscle types and features

Skeletal - voluntary and striated
Cardiac - involuntary and striated
Smooth - non-striated

34

What are pace maker cells?

Self-excitable cells that can generate an action potential without the brain. They pass on the AP to nonpacemaker cells via gap junctions between them

35

Artery vs vein vs capillary

All made of similar tissue and three similar layers, but are arranged in different ways.

Artery
- inner layer: endothelium, thick smooth muscle and thick connective tissue to withstand high pressure
- elastic: expand in systole and reduce in diastole

Vein -
- endothelium, thinner smooth muscle and thinner connective tissue as pressure is less
- lots of values to prevent backflow as blood is often going against gravity
- skeletal muscle contraction aids blood flow back to heart

Capillary
- endothelium, basal lamina
- thinner outer layer to allow diffusion and exchange of gases to occur

36

How do lipid soluble substances such as oxygen and carbon oxide cross the capillary wall?

pass through the endothelial cells

37

How do plasma proteins cross the capillary wall?

generally cannot cross the capillary wall

38

How do exchangable proteins cross the capillary wall?

vesicular transport

39

How do small water soluble substances such as sodium and potassium ions, glucose and amino acids cross the capillary wall?

through the water-filled pores

40

How does the difference between osmotic pressure and blood pressure drive fluids out and into the capillaries?

Osmotic pressure is constant. Blood pressure decreases from arteriole to venule end.

At the arteriole end of a capillary, blood pressure is greater than osmotic pressure so fluid flows out of the capillary into the interstitial fluid.
At the venule end of a capillary, blood pressure is less than osmotic pressure so fluid flows from the interstitial fluid into the capillary.

This is due to fluid moving from high pressure to low pressure. Wherever the pressure is lowest - in the capillary (osmotic) or in the blood (blood) - is where the fluid will flow.

41

2 mechanisms that regulate the distribution of blood in capillary beds

Contraction of the smooth muscle layer in the wall of an arteriole to constrict the vessel

Contraction of precapilllary sphincters to control the flow of blood between arterioles and venules

42

Blood vs systolic vs diastolic pressure

Blood pressure - the hydrostatic pressure that blood exerts against the wall of a vessel

Systolic
- the pressure in the arteries during ventricular systole
- the highest pressure in the arteries

Diastolic
- the pressure in the arteries during diastole
- lower than systolic pressure

43

Laminar vs turbulent flow

laminar - straight, does not create sound

Turbulent - not straight, can be heard as blood hits vessel wall

44

Vasoconstriction vs vasodilation

Vasoconstriction - narrowing of vessel as smooth muscle contracts causing upstream increase in blood pressire

Vasodilation - increase in vessel diameter as smooth muscle relaxes, decreasing blood pressure

45

3 constituents of blood and % volume

Red blood cells - 45%
Plasma - 55%
'Buffy coat' (platelets and white blood cells) ~1%

46

4 constituents of plamsa and function

Water - solvent

Ions (blood electrolytes) - osmotic balance, pH buffering and regulation of membrane permeability

Plasma proteins

Substances transported by blood

47

4 Plasma proteins

Albumin
Immunoglobulins
Apolipoproteins
Fibrinogen

48

What is the function of the plasma protein Albumin?

osmotic balance and pH buffering

49

What are the plama proteins immunoglobulins are what are their function?

antibodies - defence

50

What is the function of the plasma protein apolipoprotein?

lipid transport

51

What is the function of the plasma protein fibrinogen?

clotting

52

3 blood cell types and their functions

Leukocytes (white blood cells)
- defence and immunity

Platelets
- blood clotting

Erythrocytes (red blood cells)
- transport of O2 and some CO2

53

Abundance of erythrocytes

5 to 6 million per micro L (cubic millimetre)

54

Abundance of platelets

250 000 to 400 000 per micro L (cubic millimetre)

55

Abundance of leukocytes

5 000 to 10 000 per micro L (cubic millimetre)

56

Lymphoid stem cells vs myeloid stem cells

Lymphoid
- lymphocytes
- B and T cells

Myeloid
All other cell types:
- erythrocytes
- neutrophils
- basophils
- monocytes
- platelets
- eosinphils

57

Lifespan of erythrocytes

3 to 4 months

58

5 types of Leukocytes

Basphils
Lymphocytes
Eosinophils
Neutrophils
Monocytes

59

Where is average blood pressure lowest in the circulatory system?

Venae cavae

60

What would happen in the long term if the lymphatic vessels associated with a capillary bed were to become blocked?

Fluid would accumulate in interstitial areas

61

How is most CO2 carried from body tissues to the lungs?

As bicarbonate ions (HCO3-)

62

What is the Bohr shift produced by?

Changes in blood pH (lowering)

63

How does cardiac muscle differ from other types of muscle?

It contains branched cells.