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IB Biology HL > optional module d: human physiology > Flashcards

optional module d: human physiology Flashcards

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1
Q

essential nutrients are grouped into

A

Minerals: for example phosphorus, calcium, magnesium, iron.
Vitamins: for example vitamins A, C, D, K.
​Amino acids: for example histidine, tryptophan and others.
Fatty acids: for example certain omega-3 and omega-6 fatty acids

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2
Q

what are non essential nutrients

A

ones that can be made by our body eg fructose

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3
Q

what can malnutrition be caused by

A

an imbalance
an excess of nutrients

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4
Q

the human body cannot synthesise fatty acids and are therefore considered

A

essential

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5
Q

examples of fatty acids

A

omega 3 and omega 6

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6
Q

what is omega 3 needed for

A

controlling blood clotting and building cell membranes in the brain

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7
Q

what is omega 6 needed for

A

lower LDL cholesterol (the “bad” cholesterol) and reduce inflammation), and is protective against heart disease

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8
Q

what do the numbers on fatty acids relate to

A

the first double bond counting from the CH3 (methyl, position 1) group of the fatty acid

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9
Q

where can you find omega 3 fatty acids

A

in fatty fish, some veg oils, soybean rapeseed, flaxseed, brussel sprouts, kale, spinach, walnuts

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10
Q

where can you find omega 6 fatty acids

A

safflower, corn, cottonseed, and soybean oils

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11
Q

what are the nine essential amino acids

A

phenylalanine, valine, threonine, tryptophan, methionine, leucine, isoleucine, lysine, and histidine.

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12
Q

when can tyrosine be synthesised by the human body

A

when phenylalanine is present in the diet

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13
Q

which group cannot synthesise arginine

A

infants so must be present in the diet

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14
Q

conditionally essential amino acids

A

tyrosine and arginine

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15
Q

what elements are most commonly found in the human body

A

oxygen
carbon
hydrogen
nitrogen

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16
Q

what is iodine needed for

A

synthesis of thyroid hormones, which can increase basal metabolic rate, affect protein synthesis, and help regulate long bone growth

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17
Q

iodine deficiency results in

A

goitre and severe retardation

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18
Q

what is calcium and phosphorus necessary for the formation of

A

bones and teeth
muscle contraction

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19
Q

sodium and potassium are invovled in the

A

propogation of the nerve impulse

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20
Q

can vitamins be synthesised by the human body

A

no must be in the diet

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21
Q

two types of vitamin

A

water soluble and fat solublte

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22
Q

vitmin sneeded

A

retinol, fat
thiamine, water
cyanocobalamin, water
riboflavin, water
niacin, water
pantothenic acid, water
pyridoxine, water
biotin, water
folic acid, water
ascorbic acid, water
cholecalciferol, ergocalciferol
tocopherols
phylloquinone

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23
Q

main causes of malnutrition

A

Deficiency, a diet lacking in one or more particular nutrients.
Imbalance, a diet that has an inadequate intake of a particular nutrient.
Excess, a diet that has a disproportionate intake of e.g. carbohydrates, fats or proteins.

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24
Q

what controls appetitie control

A

the appetite control centre in the hypothalamus

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25
Q

when the stomach is empty,

A

gherlin is released, stimulating appetite

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26
Q

what happens when food is ingested

A

the release of peptide PYY3-36 from the small intestine (along with insulin from the pancreas and leptin from adipose tissue) inhibit appetite

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27
Q

APPETITE CONTROL CENTRE

A

D.1

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28
Q

BMI=

A

mass/height^2 (kg/m^2)

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29
Q

someone is considered obese when

A

their bmi is between 25.1 and 29.9

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30
Q

consequences of obesity

A

diabetes type 2
CHD

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31
Q

what happens in type 2 diabetes

A

the beta cells in the pancreas still produce insulin. however these patients still develop insulin resistance, which means that the insulin receptors on the cells are no longer stimulated by insulin.

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32
Q

probable causes of type 2 diabetes

A

High levels of fatty acids in the blood as a result of diets high in fat but low in fibre.
Overweight, especially obesity, associated with a lack of exercise.
Genetic makeup that influences fat metabolism.

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33
Q

symptoms of type 2 diabetes

A

Increased (elevated) glucose levels in the blood urine.
Frequent need to urinate (may lead to excessive thirst).
Tiredness and fatigue.
Some loss of weight.

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34
Q

diabetes can increase or decrease your chances of developing CHD

A

increase

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35
Q

hypertension is

A

blood pressure above the norm

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36
Q

what is CHD

A

a disease in which a substance called plaque builds up inside the coronary arteries. these arteries supply blood with oxygen to the heart muscle.

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37
Q

if saturated fatty acids combine with cholesterol it forms

A

atherosclerosis, which leads to hypertension or angina and heart attacks. can also cause damage to blood vessels increasing the risk of developing even more atherosclerotic plaques

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38
Q

prologned starvation can cause

A

permenant organ damage and death.. Initially the glycogen stores in the liver are mobilised, but once they are depleted the body has to resort to other sources of energy.

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39
Q

why does the loss of muscle and adipose tissue occur

A

by the body’s need for caloric intake and to protect the vital systems such as the nervous system and heart muscle. The body breaks down muscles and lipids to generate energy and amino acids. This process is known as catabolysis.

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40
Q

consequences of anorexia

A

BREAKDOWN OF HEART MUSCLE, electrolyte imbalance, skeletal and heart muscle reduction, reduced blood pressure and a slower heart rate. The body can become covered in a fine growth of thin hair. In female patients it can also lead to reduced or absence of menstrual cycles. Extreme cases can lead to death.

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41
Q

what is vitamin C known as

A

L-asbcorbic acid

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42
Q

can humans and animals synthesise vitamin c

A

no

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43
Q

what is vitamin c needed for

A

the production of collagen, found in skin, connective tissues, tendons, blood vessels

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44
Q

vitamin c defciency

A

scurvy

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45
Q

main symptoms of scurvy

A

Bleeding gums, gingivitis or loose teeth. Vitamin C is necessary for the synthesis of collagen, which builds and maintains tissue.
Lack of energy. Loss of weight and extreme fatigue.
Mood swings or depression. Irritability and rapid changes in mood may indicate a severe deficiency. Depression is common.
Chronic joint pain. Bleeding in the joints causes constant pain.
Suppressed immune system. Frequent diseases.
Slow wound healing and bruising. Bruising occurs easily and wounds take a long time to heal.

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46
Q

how is RDA calculated

A

A control group (group 0) does not receive any foods containing vitamin C.
Other groups (groups 1 to 10) get increasing levels of a daily supplement of vitamin C in their diet, e.g. group 1 gets 10 mg of vitamin C per day, group 2: 20 mg vitamin C per day, etc.
The control group will start to develop symptoms of scurvy.
Perhaps also groups 1 and 2 may show some symptoms, but above a certain daily supplement of vitamin C, e.g. 30 mg per day, the guinea pigs do not show the common symptoms of scurvy.
The data collected this way can be used to calculate the amount of vitamin C required by a human.

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47
Q

what is phenylketonuria

A

a genetic disease, a gene coding phenylalanine hydroxylase, an enzyme that catalyses the hydroxylation of phenylalanine to tyrosine, is mutated. This results in the inability to convert phenylalanine into tyrosine. PKU is inherited as an autosomal recessive trait which means that patients with PKU have two recessive (mutated) alleles. As the enzyme can no longer catalyse the last and rate limiting step, phenylalanine accumulates in the body.

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48
Q

medical consequences of PKU

A

Intillectual disability
Reduced growth of the head
Lack of skin and hair pigmentation
Seizures

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49
Q

what is the guthrie test

A

test for phenylketonia

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50
Q

what artifical sweetener

A

aspartame

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51
Q

what is vitamin D (calciferol) needed for

A

the absorption of calcium in the digestive system

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52
Q

what is calcium needed for

A

to build healthy bones

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53
Q

what is calcium d deficiency called

A

osteomalacia in adults (milder)
or rickets in children (more severe)

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54
Q

important roles of vitamin d

A

to maintain skeletal calcium balance by promoting calcium absorption in the intestines and maintaining calcium and phosphate levels for bone formation

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55
Q

if a breastfeeding mother has low vitamin d what happens

A

causes problems with the bone mineralisation of their infants

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56
Q

where is vitamin d found

A

oily fish, salmon, herring and tuna, egg yolk, liver, dairy

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57
Q

what does exposing human skin to uv light with a wavelength between 290-310 nm

A

triggers the synthesis of vitamin d in the skin.

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58
Q

where is vitamin d to be stored

A

fat soluble so liver

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59
Q

cholesterol is the precursor of

A

bile acids, vitamin d and steroid hormones such as progesterone and oestrogen. protects membrane integrity. presence of cholesterol in the cellular membrane enables the cell to change shape and move about.

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60
Q

types of cholesterol

A

Very Low Density Lipoprotein (VLDL), Low Density Lipoprotein (LDL) and High Density Lipoprotein (HDL)

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61
Q

which type of cholesterol has been linked with developing CHD

A

LDL
genetic factors and lack of mobility

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62
Q

how can you lower total blood cholesterol levels

A

reducing intake of dietery cholesterol
statin drugs (

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63
Q

what do statins do

A

inhibits the enzyme HMG-CoA reductase, which catalyses the second step in the pathway from Acetyl CoA to cholesterol.

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64
Q

what is a balanced diet

A

a combination of foods that contains all essential and non-essential nutrients in the right proportion. The proportion is key here.

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65
Q

what is energy measured in

A

joules

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66
Q

what is the kilojule used for

A

in food related quantities

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67
Q

1 kilocalorie =

A

4.184 kilojoules

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68
Q

total calorie intake value =

A

120-160 kcal to kg of weight

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69
Q

what proportion is protein of the TCV

A

10-15%

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70
Q

what proportion is carb of the TCV

A

35-60%

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71
Q

what proportion is fats of the TCV

A

35-50

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72
Q

amount of fibre =

A

age in years + 5g

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73
Q

how do you calulate the energy in food

A

burning a known mass of the food to test. The burning food is placed under the test tube with water. The heat liberated by the burning food is absorbed by a known volume of water. The rise in temperature is recorded (Figure 4). The energy value is calculated as temperature rise × mass of water × specific heat capacity of water (4.184 joules/gºC or 1 calorie/gºC).

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74
Q

enerfy value =

A

temperature rise × mass of water × specific heat capacity of water (4.184 joules/gºC or 1 calorie/gºC).

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75
Q

what is digestion

A

the breaking down of food particles into smaller particles. It is controlled by nervous and hormonal mechanisms.

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76
Q

why do food particles need to be digested to soluble molecules that can pass through the membranes in the intestinal tissues.

A

food particles are too large to be absorbed through the intestine walls of the digestive system.

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77
Q

how are food particles broken down to soluble molecules to pass through the membranes in the intestinal tissues

A

the exocrine glands of the digestive system secrete enzymes that hydrolyse large molecules into smaller molecules.

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78
Q

what is the autonomic nervous system / nervous control within the digestive processes divided into

A

the sympathetic and parasympathetic systems

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79
Q

what does the sympathetic nervous system do

A

controls processes involved in responses to danger, while the parasympathetic system controls homeostasis and processes related to rest and digestion.

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80
Q

what does the parasympathetic nervous system do

A

speeds up digestion when food is ingested, while the sympathetic slows it down when there is no food available.

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81
Q

divide the digestive processes into three

A

mechanical control
nervous control
hormonal control

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82
Q

examples of mechanical control of digestion

A

stomach contraction
peristalsis

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83
Q

what does hormonal control do

A

secretin
cholecystokenin
gastrin
somatostatin

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84
Q

what does secretin do

A

release of alklai and regulates water homeostasis throughout the body by acting on the kidney, hypothalamus and pituitary gland.

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85
Q

what does cholecystokinin

A

secretion of pancreatic enzymes
release of bile from gall bladder and pancreatic juice from pancreas

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86
Q

what does gastrin do

A

release of gastric acids and enzymes

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87
Q

what does somatostatin do

A

prevents and release of acid

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88
Q

what produces gastrin

A

g cells in the stomach, duodenum and pancreas, in response to physical stimulation due to the presence of food, as well as to chemical stimulation by protein

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89
Q

when gastrin is released…

A

it stimulates the production of gastric juice by the parietal cells in the gastric glands.

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90
Q

what does gastric juice contain

A

a mixture of water, hydrochloric acid and other inorganic ions, enzymes (pepsin, rennin), mucus, various polypeptides, and intrinsic factor

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91
Q

what is intrinsic factor in gastric juice

A

is necessary for absorbing vitamin B12.

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92
Q

effect of the ph of gastric juice

A

Gastric juice changes the pH of the food content from 6.7 to 2, providing acidic conditions that will enhance digestion.

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93
Q

when does gastrin stop being produced

A

When there is sufficient gastric juice present (around 1 to 1.5 litres), the production of gastrin will stop and therefore so will the secretion of gastric juice.

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94
Q

where is secretin produced

A

by special cells in the small intestine in response to the presence of acid fluid.

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95
Q

the presence of gastric acid activates prosecretin into

A

secretin

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96
Q

when secretin is released

A

it stimulates the production of alkali by the pancreas, neutralising the intestinal components.

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97
Q

when is the production of pancreatic juice stopped

A

via negative feedback when the pH of the intestine reaches 8

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98
Q

what produces cholecystokinin

A

small intestine when food is present there

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99
Q

where is bile produced and stored

A

bile is produced in the liver and stored in the gall bladder

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100
Q

bile

A

is a hunger suppressor and

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101
Q

what type of hormone is somatostatin

A

inhibitroy

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102
Q

what secretes somaatostatin

A

special cells in the stomach, duodenum and pancreas

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103
Q

how does somatostatin work

A

travels through blood to directly inhibit acid producing cells.

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104
Q

how does somatostatin work indirectly

A

by preventing the release of gastrin, CCK and secretin, thus slowing down the digestive process.

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105
Q

describe the regulatory stomach feedback mechanism

A

whereby the presence of acid in the lumen of the stomach stimulates somatostatin secretion, which in turn slows down acid secretion.

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106
Q

which system regulates acid secretion

A

the nervous system

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107
Q

what do exocrine glands have

A

ducts that carry their secretory product to the surface of the body or the lumen of the gut. These glands include the sweat, sebaceous, and mammary glands and the glands that secrete digestive enzymes.

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108
Q

how is stomach acid produced

A

by the combination of hydrogen ions (H+) and chloride ions (Cl-) produced by the epithelial cells (known as parietal cells) of the stomach lining. The release of hydrogen ions through protein carriers is coupled to the intake of potassium ions (K+) from the lumen of the stomach. This process requires energy in the form of ATP

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109
Q

what does gastric juice contain

A

hydrochloric acid and pepsin

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110
Q

what is pepsin

A

a protease that hydrolyses proteins to peptides.

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111
Q

where is pepsin

A

ound in the stomach in an inactive form as the pro-enzyme pepsinogen.

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112
Q

what releases pepsin

A

the chief cells in the lining of the stomach and is activated into pepsin by the presence of acid.

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113
Q

what releases hydrochloric acid

A

by the parietal cells of the stomach, removing 44 amino acids from pepsinogen transforming it into pepsin

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114
Q

acid condiitons in the stomach favour…

A

the hydrolysis reactions by pepsin. the optimum pH for this enzyme is 2

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115
Q

benefit of acidic conditions

A

control pathogens in ingested food. The bacteria present in food cannot survive such acid conditions.

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116
Q

benefit of the stomach mucus cover

A

avoids self-damage

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117
Q

when could the stomach produce an excess of gastric acid leading to a gastric ulcer if the mucus layer is damaged

A

if someone has eaten an excess of spicy foods, excess proteins or has extreme stress

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118
Q

symptoms of a stomach ulcer

A

stomach pain, heartburn, nausea and in some cases presence of blood in the stools.

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119
Q

what bacteria could cause stomach ulcers and why

A

Helicobacter pylori produces toxins that cause continuous gastric inflammation. The inflammatory response by the immune system damages the stomach lining.

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120
Q

Ulcers due to H. pylori are treated with a combination of medications:

A

Amoxicillin: antibiotic that directly inhibits the synthesis of bacterial cell walls.
Clarithromycin: antibiotic that prevents bacteria from growing by inhibiting the translation of peptides in the ribosome, thus inhibiting their protein synthesis.
Proton Pump Inhibitor (PPI): inhibits acidification of stomach.

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121
Q

what do Proton Pump Inhibitors do

A

block the proton pump (hydrogen-potassium-ATPase pump), responsible for the secretion of hydrogen ions (H+) in the stomach. The decrease of H+ into the lumen of the stomach reduces the amount of hydrochloric acid (HCl) produced, which makes the stomach less acidic (Figure 4), making it a suitable treatment of gastric ulcers.

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122
Q

polysachharides are digested to

A

monosacchardies

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123
Q

proteins are digested to

A

amino acids

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124
Q

lipids are digested to

A

short chain fatty acids or longer chain fatty acids

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125
Q

monosacchardies are absorbed by the

A

small intestine

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126
Q

monsaccharides destination is

A

Villus through hepatic portal vein to liver.

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127
Q

amino acids are absorbed by

A

the stomach or small intestine

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128
Q

stomach amino acids destination

A

Cells of stomach lining.

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129
Q

small intestine amino acids destination

A

Villus through hepatic portal vein to liver.

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130
Q

lipids are asorbe dby

A

the small intestine

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131
Q

lipids destination

A

Villus through hepatic portal vein to liver.
Lacteal to lymphatic system.

132
Q

adaptations of the small intestine

A

Increased surface area due to presence of villi and microvilli.
Many mitochondria to provide energy for active transport.
Presence of capillaries in villi for absorption of digested foods.
Presence of lacteal for absorption of absorbed lipids.
Presence of pinocytotic vesicles aid the uptake of fluids.
Presence of tight junctions to ensure molecules do not escape through the membrane, and to maintain a concentration gradient.
Enzymes (peptidases and disaccharidases) bound to epithelial membranes to complete hydrolysis/digestion.

133
Q

what does each villus have

A

a central lacteal whose function is mainly the absorption of fats, and capillaries that carry the rest of the absorbed molecules to other organs.

134
Q

most capillaries join to form the…

A

hepatic portal vein tthat carries blood to the liver.

135
Q

what is the structure of cells in the epithelium of the villus adapted to

A

the absorption of food

136
Q

STRUCTURE OF VILLUS

A

like d2

137
Q

what is the order of the fiv elayers of the small intestine

A

mucosa
submucosa
circular muscle layer
longitduinal muscle layer
serosa

138
Q

mucosa

A

contains the epithelium formed by enterocytes, goblet cells and endocrine cells. Enterocytes are cells that have microvilli; they digest and absorb substances. Goblet cells produce mucus and endocrine cells secrete hormones.

139
Q

submucosa

A

contains blood vessels and connective tissue.

140
Q

circular muscle layer

A

smooth muscle arranged in a circular manner.

141
Q

longitudinal muscle layer

A

smooth muscle arranged in a longitudinal manner.

142
Q

serosa

A

single layer of epithelial cells with connective tissue.

143
Q

glucose and sodium is co transported via

A

facilitated diffuseion

144
Q

how is glucose and sodium is co transported via facilitated diffusion

A

Na+ must first be transported out of the cell by active transport (along the basal membrane). This powers the co-transport of glucose and Na+ into the epithelial cells via the apical membrane. The glucose is then carried along the epithelial cell to a sugar transporter protein that allows its transport into the capillaries, which will carry it to the hepatic portal vein.

145
Q

proteins are digested by WHAT into WHAT

A

protesases into amino acids

146
Q

how are amino acids co transported with Na+

A

into the epithelial cells. Amino acid carrier proteins then carry them by facilitated diffusion into the capillaries.

147
Q

fats or lipids are emulsified in the WHAT by WHAT

A

in the intestines by bile, into smaller droplets which allows lipases to digest them into fatty acids and glycerol

148
Q

glycerol from lipids will

A

will be absorbed and used in carbohydrate metabolism

149
Q

fatty acids from lipids will

A

diffuse into the small intestine epithelial cells

150
Q

long chain fatty acids will combine with…

A

proteins to form chylomicrons

151
Q

what do chylomicrons do

A

travel to the border of the cell in the smooth endoplasmic reticulum and are expelled by exocytosis to later enter the lacteal, thus entering the lymphatic system

152
Q

what is the point in insoluble fibre

A

it increases faecal mass, thus stimulating peristaltic movements

153
Q

what is dietary fibre

A

the non-digestible carbohydrates, especially cellulose, and lignin that are intrinsic and intact in plants.

154
Q

what materials are not absorbed in digestion

A

cellulose and lignin from plant matter, bile pigments, the remains of intestinal epithelial cells and bacteria. peristalsis of the walls of the large intestine will push the faecal matter toward the rectum and eventually eliminate it through the anus

155
Q

what increases rate of transit of materials through the large intestine

A

fibre content

156
Q

what does an infection of the intestines cause

A

inflammation of the epithelial cells lining the intestine. This will reduce the absorption of water

157
Q

what is cholera

A

a disease caused by the ingestion of food or water contaminated with the bacterium vibrio cholerae. When cholera toxin is released from the bacteria in the infected intestine, it binds to the intestinal epithelial cells (enterocytes), triggering endocytosis of the toxin.The toxin then becomes an active enzyme which activates ions and water to leave the infected enterocytes, leading to watery diarrhea.

158
Q

signs and symptoms of dehydration

A

dry mouth
swelling of brain
weakness
dizziness
palpitations
drop in blood pressure
decreased urine output
kidney failure
fainting

159
Q

the liver regualtes

A

the chemical composition of the blood

160
Q

where is the liver

A

under the diaphragm in the upper right part of the abdomen

161
Q

the liver produces

A

bile
enzymes
hormones
cholesterol
triglycerides

162
Q

the liver is the site of synthesis of

A

amino aicds
proteis

163
Q

the liver stores

A

glycogen
vitamin A, B12, D and K
minerals such as iron and copper

164
Q

the liver is the remova of

A

toxins from the blood, drugs

165
Q

the liver maintains

A

blood temp and pressure

166
Q

the liver breaks down

A

red blood cells / erytrocytes

167
Q

the gall bladder

A

stores bile and regulation of blood clotting

168
Q

what supplies the liver with oxygentated blood

A

from the heart through the hepatic artery (branch of the aorta)

169
Q

where does blood leave the liver

A

through the hepatic vein which carries deoxygenated blood. this vein joins the vena cava, which returns the blood to the heart

170
Q

the hepatic vein

A

takes blood back to the heart

171
Q

the hepatic artery

A

takes blood from the heart

172
Q

the portal vein

A

brings blood from the bowel

173
Q

the liver recieves deoxygenated blood from

A

from the spleen, stomach, pancreas, gall bladder and intestines through the hepatic portal vein.

174
Q

what is the hepatic portal vein rich in

A

amino acids
glucose
vitamins
minerals
and other foods

175
Q

why does the liver have a dual blood supply

A

because it recieves oxygenated blood from the hepatic artery and deoxygenated blood from the heaptic portal vein

176
Q

how many lobes are there in the liver

A

4

177
Q

how many lobules does each lobe contain

A

100,000

178
Q

what does a lobule consist of

A

a central venule coming from the hepatic vein surrounded by six venules coming from the hepatic portal vein and sex arterioles from the hepatic artery. these blood vessels are connected by sinusoids

179
Q

interlobular vein

A

branch of hepatic vein carries away deoxygenated blood

180
Q

ateriole

A

brand of hepatic artery (brings oxygenated blood)

181
Q

interobular vein

A

branch of hepatic portal vein (brings blood from gut)

182
Q

bile duct

A

takes bile to gall bladder

183
Q

what are sinusoids

A

tubes that resemble capillaries but have a discontinuous endothelium

184
Q

layers of sinusoid

A

incomplete basement membrane
fenestrations
intracellular gap

185
Q

layers of capillaries

A

continuous basement membrane
endothelial layer
intercellular cleft

186
Q

give differnces between capillaries and sinusoids

A

very small pores vs fenestrations
continuous basement membrane v discontinuous basement membrnae
cylindircal shape vs definite shape
smaller vs larger
little intracellular space vs large
only small moleucles can pass vs leaky

187
Q

what do hepatocytes do

A

perform most of the liver functions esp storage and metabolism

188
Q

describe hepatocyteds

A

These cells are large (around 25 μm) and constitute around 80% of the total liver cells. Their nucleus is round and found in the centre of the cell. These cells are capable of regenerating when exposed to toxic substances. Liver regeneration involves the replication of hepatocytes followed by the replication of other liver cells.

189
Q

liver regeneration

A

Liver regeneration involves the replication of hepatocytes followed by the replication of other liver cells. Once cell proliferation is completed, the newly divided cells undergo restructuring and reformation of the extracellular matrix to complete the process. During regeneration, liver function is only partially affected. Because human liver cells regenerate it has become possible to use partial livers from living donors for transplantation, thereby increasing the number of organs that are available for transplantation.

190
Q

what are plasma proteins

A

synthesised in hepatocytes mainly in the rough endoplasmic reticulum (rER) and processed in Golgi complexes.

191
Q

function of hepatocytes

A

(main liver cells) degradation of toxins
exocrine function in secretion of bile

192
Q

what are kupffer cells

A

white blood cells (macrophages) that break down red blood cells

193
Q

what do kupffer cells do

A

involved in the recycling of erythrocytes, as you will see later in this subtopic.

194
Q

what do bile canaliculi do

A

carry bile to the bile duct that leads to the gall bladder where bile is stored until it is used in the small intestine

195
Q

how is glucose dealt with in the liver

A

hepatocytes in the liver absorb most of the glucose and store it as glycogen

196
Q

fatty acids in the blood passing through the liver are

A

absorbed by hepatocytes and metabolised to produce energy in the form of atp.

197
Q

what do hepatocytes synthesise

A

lipids such as triglycerides, cholesterol and phospholipids.
These lipids can be bound to proteins forming lipoproteins, which are now soluble in blood plasma and can therefore be transported in blood to all the body

198
Q

much of the cholesterol produced by hepatocytes gets

A

excreted from the body as a component of bile.

199
Q

what do Endoplasmic reticulum and Golgi apparatus in hepatocytes produce

A

plasma proteins that include fibrinogen used in blood clotting, and albumin that transports hormones and maintains the blood pH.

200
Q

what happens when amino acids are no longer necessary

A

hepatocytes remove the amine group from the acid group (deamination). The acid group of the amino acid is used to produce energy or new glucose molecules while the amine group is converted into ammonia. As ammonia is toxic, it is transformed into urea, which is then eliminated by the kidneys in urine.

201
Q

FIGURE 1 METABOLISM OF NUTRIENT SIN THE LIVER

A

D3

202
Q

what is detoxification

A

the liver gets rid of drugs, hormones and other toxins.

203
Q

what if the liver cannot break down sunstnaces

A

it attatchces these substances to other organic groups such as a glycerine which allows the kidneys to recognise them as unwanted waste material and are therefore excreted.

204
Q

what is ethanol oxidised into

A

acetaldehyde, a toxic substance, by the hepatic enzyme alcohol dehydrogenase. Acetylaldehyde is converted into a less toxic substance, acetate, by aldehyde dehydrogenase. Acetate is then broken down to acetyl-CoA that can enter fatty acid metabolism or be used in the Krebs cycle. If acetaldehyde is not broken down immediately, it can combine with proteins that induce liver injury. Excess of alcohol can damage the liver, causing cirrhosis.

205
Q

is cholesterol essential

A

no, most cholesterol molecules are synthesised in the liver

206
Q

as most animal cells require cholesterol for membrane synthesis,

A

a small portion is added to the membranes of hepatocytes, and the rest is exported as lipoproteins or bile salts

207
Q

what is cholesterol a precursor for

A

bile salts, steroid hormones (oestrogen and progesterone) and vitamin D.

208
Q

how is cholesterol synthesis regulated

A

according to its concentration in cells. This depends on the amount ingested in diet, and the regulation is performed by the hormones glucagon (inactivating its synthesis) and insulin (activating its synthesis).

209
Q

STRUCTURE OF CHOLESTEROL

A

D3

210
Q

is cholesterol insoluble or soluble

A

insoluble, so it must be carreid as plasma lipoproteins

211
Q

what is cholesterol carried as

A

plasma lipoproteins

212
Q

Different combinations of lipids and proteins produce particles of

A

different densities.

213
Q

high density lipoproteins (HDL) contian more

A

protein

214
Q

low-density lipoproteins (LDL) contain more

A

lipids

215
Q

where are LDL’s and HDL’s produced

A

plasma, however a small amount is synthesied in the liver.

216
Q

function of LDL

A

to transport cholesterol from the liver to the organs.

217
Q

function of HDL

A

to transport cholesterol from tissues to the liver

218
Q

fats can deposit in arteries causing an…

A

atheroma or plaque

219
Q

what are atheromas or plaques caued by

A

white blood cells (foam cells) and LDL, where molecules of LDL deposit in the blood vessels and can become oxidised. This will cause atherosclerosis of the walls of the arteries

220
Q

atherosclerosis

A

narrowing of arteries due to plaque

221
Q

arteriosclerosis

A

hardening of arteries

222
Q

what can atherosclerosis cause

A

cardiovascular disease and stroke

223
Q

what happens if the artery leading to the artery (coronary artery) is clogged

A

the cells of the heart will not receive enough oxygen and can therefore die. These cells are replaced by fibres causing coronary heart disease (CHD). If the artery leading to the head (carotid artery) is affected, this can lead to a brain stroke.

224
Q

which cholesterol is considered ‘good’

A

HDL as it removes LDL from blood by transporting it to the liver and helps to maintain the endothelium of the blood vessels, thus avoiding coronary heart problems.

225
Q

what are bile salts

A

emulsify fats

226
Q

what is emulsification

A

breaking fats down into smaller droplets to increase their surface area to allow enzymes to work better

227
Q

where are bile salts synthesised

A

by the liver from surplus cholesterol, and may be modified by bacteria in the intestines.

228
Q

Bile salts are ______ from the ______ into the ______

A

reabsorbed from the
intestines into the
liver

229
Q

bile salt aid in the

A

digestion and absorption of dietary lipids and fat-soluble vitamins.

230
Q

the liver produces how much bile a day

A

on elitre

231
Q

bile travels from the liver to where

A

carried by the bile canaliculi to the bile duct, which carries it to the gall bladder to be stored.

232
Q

composition of bile

A

97% water
bile salts
cholesterol
fatty acids
bilirubin (from breakdown of erythrocytes)
inorganic salts

233
Q

what can diseases of the liver be caused by

A

pathogens, metabolic problems, toxins such as drugs or alcohol.

234
Q

what is jaundice

A

Jaundice is a condition where the skin and white of the eyes turn yellow

235
Q

what is jaundice caused by

A

the presence of bilirubin in extracellular fluid.

236
Q

bilirubin is produce from

A

haemoglobin breakdown in erythrocyte recycling in the liver. The metabolism of haemoglobin accounts for 65% to 80% of the total bilirubin production.

237
Q

what does bilirubin in blood irreversabily bind to

A

albumin (a plasma protein), forming conjugated bilirubin that travels to the liver, which removes it from the plasma.

238
Q

what happens when the liver is not able to remove the bilirubin from blood

A

its level may rise (especially in the unconjugated form) and the skin and eyes may begin to appear jaundiced.

239
Q

when does jaundice occur

A

Increased destruction of red blood cells.
Immaturity in the conjugation of bilirubin (greater in premature babies).
Genetic diseases (e.g. Gilbert syndrome).
Defects in the secretion of conjugated bilirubin from hepatocytes (in liver damage).
Defects in transit of bilirubin to intestines (e.g. with bile duct obstruction).
can also be caused by the use of drugs, genetic factors, malaria or anemia.

240
Q

a high level of bilirbin in the blood is a sign of

A

liver malfunction

241
Q

effects of jaundice

A

range from clinically unnoticeable to severe brain damage and even death. Jaundice is usually a symptom of hepatitis or liver cancer.

242
Q

what is cirrhosis

A

a disease where the damaged liver tissue is replaced by scar tissue, as shown in Figure 2. Not only does this affect the functioning of liver cells, but also interferes with the blood supply to these cells.

243
Q

symptoms of cirrhosis

A

weakness, fatigue, jaundice and bruising.

244
Q

liver biopsy will

A

confirm the presence of scars

245
Q

tretment of cirrhosis

A

no cure. liver transplant

246
Q

what causes cirrhosis

A

Excessive alcohol or drug consumption may cause liver cirrhosis. Other causes of cirrhosis include chronic viral hepatitis B or C, chronic bile duct obstruction, fatty liver disease, excess of iron, cystic fibrosis and Wilson’s disease.

247
Q

Why should alcoholics be entitled to receive a liver transplant?

A

Everybody has the right to live.
They can change their lifestyle and stop drinking.
They might be the only support for a family.
Many people care for them.

248
Q

Why should they not receive a liver transplant?

A

They caused the liver damage by their own choice of drinking.
They must put up with the consequence of their own reckless attitude.
Other people deserve the transplant more.
They can relapse back into drinking and damage the new liver.

249
Q

what does the structure of the cardiac muscle cells allow

A

propagation of stimuli through the heart wall.

250
Q

where is the nucleus of the cardiac muscle cell found

A

in the centre of the cell

251
Q

what do cardiac muscle cells have a lot of

A

mitochondria and glycogen granules

252
Q

how is cardiac muscle different to skeletal muscle

A

it has numerous, short, cylindical cells, arranged end to end resulting in long branched fibres

253
Q

what is an inteercalated disc

A

the attatchment site between cardiac muscle cells. appears as a linear structure transverse to muscle fibre

254
Q

what do intercalated discs represent

A

the attatchment site between adjacent cells.

255
Q

what do intercalated discs contain

A

adhering junctions between cells that hold cells together and gap junctions, which allows communication between cells

256
Q

what are gap junctions

A

arrays of densely packed protein channels that permit intercellular passage of ions and small molecules. Electrical activation of the heart requires cell-cell transfer of current via gap junctions.

257
Q

what is the refractory period

A

where the cells cannot contract for a second time

258
Q

purpose of refractory period

A

ensres that the contraction or systole of the heart is separated by a resting period or diastole

259
Q

what causes the heartbeat

A

the pontaneous rhythmic contraction of cardiac muscle

260
Q

where does the contraction causing the heartbeat start

A

sinoatrial node (SA), a group of specialised cardiac muscle cells found where the superior vena cava joins the right atrium. Signals from the sinoatrial node that cause contraction cannot pass directly from atria to ventricles. 
Instead the impulse spreads along the atria to the atrioventricular node (AV), from where it spreads to the ventricle. There is a delay between the arrival and passing on of a stimulus at the atrioventricular node. This delay allows time for atrial systole before the atrioventricular (tricuspid and bicuspid or mitral) valves close. The blood therefore leaves the atria to the ventricles when the atrial systole occurs.

261
Q

what does the dealy between the arrival and passing of a stimulus at the AV node gives time for

A

the atria to contract before the AV valves close

262
Q

what forms the bundle of his

A

specialised fibres grouped to form a bundle in the interventricular walls

263
Q

what does the bundle of his split into

A

two branches that go to the left and right ventricles, leading to purkinje fibres. these carry the impulse at a very high speed

264
Q

what is the ventricular contraction called

A

the systole

265
Q

what is the diastole

A

when the heart is relaxed

266
Q

what part of the heartbeat is the closing of the AV valves

A

the first part

267
Q

what is the second part of the heartbeat

A

the closing of the semilunar valves

268
Q

what is an action potential

A

an electrical event associated with different concentrations of ions across membranes.

269
Q

what does the plateau of the action potential in cardiac muscle do

A

prevents the heart from contracting before time

270
Q

what is the plateau in action potential

A

due to the balance between the potassium ions leaving the cell and the calcium ions coming in. This phase maintains depolarization for a longer time.

271
Q

why are pacemaker rhytms considered myogenic not neurogenic

A

as one action potential is completed, immediately another action potential is generated in the membrane, even in the absence of nerve impulse.

272
Q

what is heart rate

A

number of times the heart contracts in one minute (bpm) obtained through pulse

273
Q

normal heart rate

A

50-100 bpm

274
Q

factors that increase heart rate

A

gender
physical activity
body size
temperature
altitude
posture
stress
eating
sodium and calcium ions inblood
drugs

275
Q

factors that decrease heart rate

A

age
potassium ions

276
Q

bradycardia

A

heart beating too slowly

277
Q

tachycardia

A

heart beating too quickly

278
Q

arrhythmia

A

heart beating irregualrly

279
Q

what does a pacemaker consist of

A

a battery powered generator (that sends out electrical impulses) and wires with electrodes to connect to the heart muscle. If the pacemaker senses that the heartbeat is above a certain rate, it will stop sending signals to the heart. The pacemaker can also sense when the heartbeat slows down too much. It will automatically turn back on and start pacing the heart again.

280
Q

how is a pacemaker inserted

A

A small cut is made on the left side of the chest or abdomen and the generator is placed under the skin at this location. The pacemaker can have one lead leading to the right atrium or two leads, one to the right atrium and another to the right ventricular walls (Figure 1). Another type of pacemaker also includes a lead to the left ventricle.

281
Q

what does an ECG do

A

check the electrical activity of the heart

282
Q

how are the resulsts of an ECG displayed

A

amplified in the ECG machine and displayed on an oscillosocope or recorded on moving paper

283
Q

what does an ecg graph show

A

voltage variations over time

284
Q

what is the r-r intercal between successive beats allowing the calculation of the heart rate

A

difference between peaks

285
Q

what is blood pressure

A

the pressure of blood on the walls of an artery during a systole. (highest value recorded) and a diastole (lowest value).

286
Q

during the heart contraction blood flows

A

out of the heart at a high pressure through arteries

287
Q

when is blood pressure lowest

A

heart relaxation (diastole)

288
Q

what measures blood pressure

A

sphygmomanometer
consists of a inflatable cuff and measuring device

289
Q

HOW TO TAKE

A

BLOOD PRESSURE

290
Q

what is hupertension

A

high blood pressure

291
Q

what is hypotension

A

low blood pressure

292
Q

causes of hypertension

A

gender
obesitu
age
lack of exercise
caffeine
alochol
smoking
sodium
stress
anxiety
genetic

293
Q

consequences of hypertension

A

stroke
blindness
arteriosclerosis
heart attack/failure
kidney failure

294
Q

stroke as consequence of heart attack

A

occurs due to a reduced or interrupted supply of blood to the brain. The brain does not get enough oxygen or nutrients, which causes brain cells to die.

295
Q

blindness as consequence of heart attack

A

can happen because of the ruptured capillaries in the retina or optic nerve or damage to the area of the brain responsible for processing images.

296
Q

arteriosclerosis as consequence of heart attack

A

s the hardening of arteries, restricting the flow of oxygen and nutrients to tissues. Atherosclerosis is a special kind of arteriosclerosis. It is caused by the damage of arteries and subsequent formation of scar tissue. A plaque is formed when cholesterol and other lipids build up on this scar tissue. The plaque makes platelets release factors that cause the formation of a clot over the plaque, forming a thrombus. The thrombus blocks the flow of blood to tissues, causing thrombosis. If a thrombus (or clot) occurs in the coronary artery, the supply of blood and oxygen to the areas of the heart muscle is blocked. This causes irregular heartbeats and can lead to coronary heart disease (CHD).

297
Q

what is epidemiology

A

investigates all the factors and effects that determine the presence or absence of diseases and disorders in a population.

298
Q

what is CHD

A

the name for decreased blood flow and oxygen to the heart muscle caused by narrowed heart arteries. It is also called cardiac ischemia or ischemic heart disease.

299
Q

what is heart disease caused by in LEDC

A

viral or bacterial infection and nutritional deficinies

300
Q

what is heart disease caused by in MEDC

A

hypertension
high fat diets
cigarette smoking
sedentary lifestyles

301
Q

what could genetic dispostiion to CHD be caused by

A

insulin resistance sydnrome
chances of diabetes
elevated triglyceride
HDL cholesterol concentrations

302
Q

what is ventricular fibrillation

A

the interruption of the electrical impulses that control heartbeat. This can be caused by the loss of blood flow to the heart or a heart attack. It often begins with ventricular tachycardia (rapid heart beating) and leads to low blood pressure because the ventricles are not able to pump hard enough. The symptoms are chest pain, dizziness, nausea, heartburn, fluttering heartbeat, fainting, coma, nerve function loss, changes in mental function and eventually death.

303
Q

benefit of cpr

A

CPR can keep oxygenated blood flowing to the brain and other vital organs until more definitive medical treatment can restore a normal heart rhythm. It is quite a simple procedure that can be done by anyone if a doctor is not found in the proximity. To learn CPR properly, you can take an accredited first-aid training course, including CPR and how to use an automated external defibrillator (AED). After calling for emergency medical help, this is what you need to do:

304
Q

CARRYING OUT

A

CPR

305
Q

Hormones are not

A

secreted at a uniform rate and exert their effect at low concentrations.

306
Q

hormones can be

A

steroid or peptide

307
Q

what glands are involved in the production of hromones

A

pituitary gland
hypothalamus
thymus
thyroid
parathyroid
oancreas
ovaries
mammary glands
adrenal glands
kidneys
testes

308
Q

most hormones are regualted via

A

negative feedback mechanisms

309
Q

hormones are involved inthe regulation and control of

A

Metabolism
Development
Homeostasis
Digestion
Excretion
Sleep
Reproductive cycles
Growth
Secondary sexual characteristics
Sensory perception
Mood
Hunger
Birth
Lactation

310
Q

major endocrine glands

A

pituitary
pineal
thymus
thyroid
adrenal
pancreas
testes and ovaries

311
Q

what are hormones

A

chemical messengers secreted by cells or glands of the endocrine system that control and regulate the activity of other cells or glands in other parts of the body.

312
Q

which hormones are the steroid hormones

A

the sex hormones (oestrogen, progesterone, testosterone) and those from the adrenal cortex (aldosterone, cortisol and estradiol).

313
Q

what are the protein hormones

A

all except cortisol oestrogen progesterone testosterone

314
Q

negative feedback def

A

is seen when the output of a pathway inhibits inputs to the pathway.

315
Q

Synthesis (hormones)

A

the rate of production can be regulated by positive or negative feedback.

316
Q

delivery (hormones)

A

n endocrine glands, this is regulated by blood flow.

317
Q

elimination (hormones)

A

hormones are metabolised and excreted once their half-life is over.

318
Q

steroid hormones are generally synthesised from

A

cholesterol in the ovaries or testes and in the adrenal glands

319
Q

are steroid hormones polar

A

no they are fat soluble, they can pass through the phosopholipids of the cell membrane

320
Q

what do steroid hormones do once inside the cell

A

some bind to a receptor in the cytoplasm and others to a receptor in the nucleus

When the steroid hormone joins a receptor in the cytoplasm, two receptor subunits join together to form one functional DNA-binding unit that can enter the cell nucleus. Once in the nucleus, the receptor-hormone complex binds to specific DNA sequences and regulates transcription of its target genes.

When the steroid hormone binds to the receptor inside the nucleus, the receptor undergoes a conformational change that renders it activated to recognise and bind to specific nucleotide sequences. When the receptor-hormone complex interacts with DNA it alters the transcriptional level (responses can be either activating or repressing) of the associated gene.

The RNA produced is translated into new proteins, for example, enzymes involved in different metabolic processes. This method of action is relatively slow as it involves synthesis of proteins

321
Q

what do peptide hormones do

A

bind to receptors in the plasma membrane of the target cell. They cannot enter the cell as they can’t pass through the cell membrane. Binding of hormones to membrane receptors activates a cascade mediated by a second messenger inside the cell. 
The sequence of events that results in hormone action is relatively rapid.

322
Q

what is epinephrine

A

peptide hormone produced by the adrenal glands in response to stress and during exercise

323
Q

waht does epinephrine do

A

attatches to receptors on the membrane of the heart cell called adrenergic receptors which are coupled to a g protein. when the epinephrine joins the adrenergic receptor, the G-protein sends a message to the enzyme adenylyl cyclase. This in turn leads to the activation of the secondary messenger, cyclic adenosine monophosphate (cAMP), which induces smooth muscle relaxation, producing vasodilation and increased contraction of the cardiac tissue.

324
Q

what is somatotropin

A

protein hormone synthesis by the anterioir pituitary gland. involved in the regualtion of bone and muscle growth. HGH is sometimes used in sports to induce anabolic effects.

325
Q

adverse effects of anabolic steroid hormones

A

Increase in size of testes and ovaries, impaired spermatogenesis, growth of breasts in males.
Psychiatric disturbance.
Toxic to the liver.
Dyslipidemia (raised LDL and triglycerides and reduced HDL).
Hypertension.
Increased coagulation and platelet aggregation.
Exaggerated left ventricle growth.

326
Q

what happens when HGH is mixed with testosterone

A

It has been proven that HGH significantly reduces body fat mass and increases body cell mass and sprint capacity when administered together with testosterone.

327
Q

D.5 Hormones and metabolism
Hypothalamus and pituitary gland

A

…..

IB Biology HL (15 decks)

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