Structure and function of the blood vessels and heart Flashcards

1
Q

A myocardial infarction causes and caused from

A

death of cells due to lack of nutrients and oxygen-Cause - acute obstruction
of coronary artery - often blood clot

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2
Q

The cardiovascular system (CVS) speeds

A

up gas and solute transport over long distances (convection)

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3
Q

Diffusion is fast over

A

short distances, very slow over >1 mm

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4
Q

Function of the Cardiovascular System

A

delivery of O2 and nutrients to each cell

removal of CO2 and waste products from each cell

communication between organs through transport of hormones and other extracellular mediators

temperature regulation

crucial hydrodynamic device in sexual reproduction!

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5
Q

Blood pressure is determined by three main factors

A

cardiac output (pumping of the heart), the blood vessels or vasculature which not only carry the blood but are responsible for the resistance that creates the blood pressure and the various fluid compartments

peripheral resistance and blood volume

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6
Q

Blue color represents

A

blood that is only
partially oxygenated.

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7
Q

Cardiovascular circulation can be divided into

A

the systemic and pulmonary (lung) circuits with the heart as the central pump

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8
Q

What is the composition of blood?- 70kg individual 5.5l blood

A

Plasma (water, ions, proteins, nutrients, hormones, metabolic wastes, gases, etc)- 55%

Leucocytes
and = “ buffy coat ”
Platelets- immunity cells

oxygen transport- Erythrocytes = 45%
(Hematocrit = 45%)

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9
Q

Most of blood is distributed in

A

the veins and venules (act as a blood reservoir)

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10
Q

Blood Flow (at rest)- most of the blood id where

A

skeletal muscle, kidney and abdominal organs

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11
Q

Majority of pumping is in parallel ….

A

which means that all flow through organs is not linked. Some exceptions including intensines which run into liver….carry food

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12
Q

A change in heart flow can lead to

A

reduction of oxygen which causes a pain called angina

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13
Q

All blood vessels contain endothelial cells ….

A

but vary in the thickness of the smooth muscle and connective tissue

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14
Q

away from the heart- arteries to arterioles to capilllaries ( exchange )

A

venules to veins towards the heart

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15
Q

Arteries contain- structure

A

a large lumen and a thick layer of
smooth muscle (tunica media) and connective tissue (tunica adventitia)

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16
Q

Thick layer of elastic smooth muscle acts as

A

a pressure reservoir

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17
Q

contraction- systole

A

stretch (absorbing pressure)

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18
Q

relaxation- Diastole

A

passive recoil( releasing pressure)

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19
Q

Arterioles contain -structure

A

a thin muscular wall and a small lumen

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20
Q

Contraction of the smooth muscle regulates the diameter of the lumen

A
  • Determine blood flow to organs
  • Major determinant of mean arterial pressure
21
Q

Capillaries have a- structure

A

single layer of endothelial cells
Exchange of nutrients, oxygen and waste across the capillary wall but NOT proteins
Intercellular clefts and fused vesicles channels assist the exchange.

22
Q

Venules and veins contain - structure

A

thin walls, large diameter lumen and valves
Thin small muscle layer and large diameter lumen – allow storage of large blood volume (~ 60% of total blood volume)

23
Q

Return of venous blood to the heart is facilitated by

A

valves and the skeletal muscle pump ‘
Varicose veins – broken valves allow the blood to flow backwards under gravity

24
Q

Varicose veins

A

broken valves allow the blood to flow backwards under gravity

25
Q

Coronary arteries branch off the

A

aorta (coming from left ventricle)

26
Q

Most deoxygenated blood drains back into the right atrium via a

A

single vein (coronary sinus)

27
Q

Coronary Arterial Disease

A

insufficient blood flow (ischemia) is associated with chest pains (angina) often radiating down left arm
severe blockage leads to damage (death) of the heart region and myocardial infarction or heart attack
ventricular fibrillation and death (heart attack)

28
Q

Causes of Coronary Arterial Disease

A

Atherosclerosis (thickening of the coronary arteries)- statins used to decrease cholesterol
Blood clot (coronary thrombosis)
Drugs
Surgery

29
Q

ischemia

A

insufficient blood flow

30
Q

Treating coronary artery disease

A

Balloon angioplasty and stents

Dye shows blockage (occlusion) of right coronary artery
Guide wire used to insert a balloon which is inflated to allow the insertion of a wire stent
Repaired vessel

31
Q

Cerebral spinal fluid (CSF)

A

CSF cushions the brain against damage (brain is floating in CSF)
CSF produced in specialised epithelial cell called choroid plexus (500ml/day)
Circulation around brain and spinal cord driven by changes in circulation, respiratory and posture
Passes into vein via valves at the top of the skull (arachnoid villus)

32
Q

Brain has no stored glycogen

A

and requires constant supply of glucose and oxygen (damage within minutes) – 15% of resting blood flow
Loss of blood supply and death of neurons - stroke

33
Q

oedema

A

Failure to regulate fluid compartments leads to

34
Q

Osmosis:

A

net diffusion of water across a selectively permeable membrane from a region of high water concentration to one that has a lower water concentration (low particle concentration to high particle concentration)

35
Q

One osmole (osm) =

A

1 mole (6.02 x 1023 ) of solute particles in 1L, eg.

1 M glucose = 1 Osm
1 M NaCl = 2 Osm1 M MgCl2 = 3 Osm1 mole

36
Q

Osmolarity

A

Osmolarity

37
Q

osmosis- Example of a selectively permeable membrane
(only water can move)

A

Cellular membranes
Permeable to water
Impermeable to solutes (ions) such as Na+, Cl-, K+ etc
Osmosis determines distribution of water (i.e. size of intracellular and extracellular compartments)

38
Q

Colloid osmotic pressure

A

pressure exerted by the higher levels of protein in the plasma compared with the interstitial fluid

draws water back into plasma by osmosis (absorption)
Colloidal osmotic (absorption)

39
Q

Hydrostatic Pressure

A

is the force exerted by the blood upon the capillary walls i.e. blood pressure
Hydrostatic pressure drives blood from plasma into interstitial space
Hydrostatic (filtration

40
Q

Net OUTWARD Filtration

A

Hydrostatic Pressure Dominates
- forced out

41
Q

Net INWARD Filtration

A

Colloid Osmotic Pressure Dominates
- forced back in

42
Q

Lymphatic system

A

Lymph system is parallel vascular system with two major functions:
Draining fluid from the tissues and returning to the cardiovascular system
Maintenance of the immune response

43
Q

Lymphatic system : Drainage

A

Fluid (plasma) passes (8l/day) from blood into the interstitial area (surrounds cells in the tissues)

Excess fluid passes into lymph capillaries, through lymph nodes (detection of infection) before passing back to blood stream at the neck (largest is thoracic duct that drains into subclavian vein)

Lymph vessels contain valves and fluid is forced along by action of muscles and breathing (respiration). Larger lymph vessels are surrounded by smooth muscle that contract spontaneously and driven by pacemaker cells (~ heart)

Collects fats from the intestines/liver and deposits into veins

44
Q

Lymphatic system : Immunity

A

Lymph fluid contains white immune blood cells (lymphocytes, macrophages, dendritic cells)

Collects antigens (proteins produced by pathogens)

Antigens recognised by B-lymphocytes in lymph nodes leading to activation of immunity.

B-cell proliferate to produce antibodies. Lymph nodes also contain multiple other immune cells (swelling can occur)

45
Q

Increased Capillary Hydrostatic Pressure (both ends)

A

Heart Failureexcessive kidney retention of waterincreased arteriolar resistance
high venous pressure

46
Q

Decrease in colloid osmotic pressure

A

Reduction in plasma proteins
loss of proteins in urine (kidney failure)
loss of protein in denuded skin areas (burns)
malnutrition

47
Q

Blockage of lymph nodes

A

Cancer
Infections
Surgery

48
Q

Intracellular oedema

A

eg. friction blister of the skin

Depression of metabolic systems of the tissues and lack of adequate nutrition to the cells eg. ischaemia: reduced activity of Na+ pumps leads to accumulation of Na+ in cells, causing osmosis of water into cells