Homeostatic Mechanisms Flashcards
1
Q
What are hormones?
A
Chemical messengers in the blood
2
Q
Where are hormones made from?
A
The Endocrine organs
3
Q
What is homeostasis?
A
This is the maintenance of constant or steady state conditions within the body
4
Q
What 4 things does homeostasis control?
A
Blood sugar, CO2, blood pH and temperature
5
Q
Why is homeostasis important (3 reasons)?
A
cells to function correctly,
chemical reaction to occur at correct point
allows organisms to be independent of fluctuations in external environment
6
Q
What is it called when there is a change in the body?
A
Stimulus
7
Q
What detects this change?
A
Receptors
8
Q
What causes a response to this change?
A
Control centre in the brain
9
Q
What responds to this change?
A
Efector
10
Q
What is this response called?
A
Negative feedback
11
Q
What does switching off this mechanism prevent?
A
Overcorrection
12
Q
What organ controls blood glucose?
A
The pancreas
13
Q
What specifically detects blood glucose change in this organ?
A
The Islets of Langerhans
14
Q
What does the beta cells in the I.L detect?
A
Increase in blood glucose level
15
Q
What causes an increase in blood glucose?
A
When a meal is being digested and absorbed into the blood
16
Q
What does an increase in blood glucose cause to be released?
A
Insulin
17
Q
What happens to all body cells when insulin is released?
A
They take up more glucose
18
Q
What happens to the rate at which glucose is taken up when insulin is released?
A
It increases
19
Q
What is glucose converted to when insulin is released?
A
Increased rate of glucose to fat storage
20
Q
What also is glucose converted to for liver and muscle cells?
A
Glycogen
21
Q
What is released when there is a decrease in blood glucose level?
A
Adrenaline and Glucagon
22
Q
What can cause this decrease in blood glucose?
A
Respiration
23
Q
What do liver cells do to glycogen when blood glucose decreases?
A
Covert back to glucose and released
24
Q
What happens to amino acids when blood glucose decreases?
A
Convert back to glucose
25
What happens to rate of reactions when blood glucose level is low?
Decreases
26
Where is glucagon released from?
Alpha cells in the Islets of Langerhans
27
Where is adrenaline released from?
Adrenal glands
28
What happens when more adrenaline is released?
Liver cells increase rate of conversion of glycogen to amino acids to glucose
29
What are the 2 ways to monitor blood glucose?
Blood meter and clinistix
30
What colour does clinistix turn to when glucose is present?
Blue/purple
31
How does the blood meter detect glucose?
You prick your finger and then drop blood onto the test strip. The strip is then put into the meter and blood glucose is measured in mmoll-1
32
What is it called when there is excess blood glucose in the blood or urine?
Diabete Mellitus
33
What is diabetes?
When the blood fails to regulate blood glucose
34
When is type 1 diabetes often diagnosed?
Birth or later
35
What in the body is unable to regulate during type 1 diabetes?
The beta cells produce little or no insulin
36
How is type 1 treated?
Insulin injections
37
When is type 2 diabetes often diagnosed?
Middle age, often associated with obesity
38
What happens in the body with type 2 diabetes?
The body produces insulin, however the target cells are resistant so pancreas increases insulin to the point it becomes damaged
39
What are the 2 ways to treat type 2 diabetes?
Medication or low carb diets
40
Where is thyroxine released from?
Thyroid glands - pituitary gland and hypothalamus
41
How do you gain thyroxine in your diet?
By iodine you can get this from cod, seaweed or eggs
42
What does thyroxine do? (top 4)
Increases BMR
Increases heart rate
Increases cardiac output
Increases breathing rate
43
What is it called when there is too much thyroxine in the blood?
Hyperthyroidism from overactive thyroid creating a tumour
44
What are the symptoms of too much thyroxine?
Restless
Weighloss
45
What is the swelling on your neck called with too much thyroxine?
Goitre
46
How is too much thyroxine treated? (3 ways)
Drugs
Radioactive iodine
Surgery
47
What is an underactive thyroid called?
Hypothyroidism
48
What causes an underactive thyroide?
Immune disorders or drugs
49
What are the symptoms of an underactive thyroid?
Feeling low, weight gain and tiredness
50
How is an underactive thyroid treated?
Tablets which replace thyroxine
51
What would cause the blood to be too concentrated?
Too much sodium and too little water
52
What occurs when the blood is too concentrated?
Water leaves cells by osmosis and shrinks
53
What would cause the blood to be too dilute?
Too much water and too little sodium
54
What occurs when the blood is too dilute?
Water enters the cells by osmosis and the cells swell
55
What are sodium and chloride ions known as?
Electrolytes
56
How do you gain sodium and chloride ions?
Food and drink which is absorbed in ileum
57
How do you lose sodium and chloride ions?
Through urine and sweat
58
What are sodium ions needed for? (5 reasons) WIMAP
Control water balance
Muscle Contraction
Control Blood Pressure
Acid/base balance
Transmission of nervous impulses
59
What are chloride ions needed for? (3 reasons) WAA
Control water balance
Acid/base balance
HCL in stomach which acids digest
60
What can any sodium imbalance lead to?
Death or coma
61
What is excess sodium known as?
Hypernatremia
62
Name some of the symptoms of excess sodium? (5)
Muscle Twitching
High blood pressure
Brain dysfunction and confusion
Severe thirst
Heart failure
63
What is low sodium known as?
Hypnoatremia
64
What are some of the symptoms of low sodium? (4) DILS
Shock
Low blood pressure
Dehydration
Irregular heart beat
65
What hormone controls sodium ions?
Adolesterone
66
What gland detects a change in blood sodium?
Pituitary Gland
67
What gland releases adolesterone?
Adrenal Glands
68
What happens to the urine if blood sodium has increased?
More sodium excreted in urine
69
What do the kidneys do if sodium has increased in the blood?
Reabsorb less sodium
70
What hormone controls water balance?
Antidiuretic
71
What can the control of water balance also be known as?
Osmoregulation
72
What detects a change in blood concentration and where is this located?
Osmoreceptors in the hypothalamus
73
What gland responds to the osmoreceptors?
Pituitary gland
74
What does the pituitary gland release if blood is more concentrated?
More ADH
75
What happens to urine if the blood is more concentrated?
There is a smaller volume of concentrated urine
76
What does ANP stand for?
Atrial Natriuretic Peptide
77
Where is ANP produced?
Atrial Muscle cells
78
What is the normal pH range?
7.35 to 7.45
79
What is the definition of blood pH?
Measure of concentration of H+ ions present
80
Do acids have a higher or lower pH?
Lower
81
What happens to the concentration of H+ ions in acids?
There is a higher concentration as there are H+ ions released
82
What does alkalines (bases) do to blood pH?
They raise blood pH
83
What happens to H+ions in regards to alkalis in blood pH?
Alkalis combine with H+ ions which decreases the concentration of H+ ions.
84
What keeps the pH constant?
Buffer
85
What does the body produce during normal metabolism?
More acid waste than base
86
How does respiration cause more acid waste than base?
CO2 is produced which turns into carbonic acid which releases H+ ions
87
What 2 other factors cause more acid waste than base?
Food consumed and metabolism of proteins and fats
88
What are the 3 ways to control blood pH?
Buffer molecules
Respiratory mechanism
Kidney
89
What are the two ways that buffer molecules can control blood pH?
Can combine with H+ ions to stop pH falling
Can release H+ ions to prevent pH rising too high
90
What acid can release and absorb H+ ions?
Carbonic Acid
91
What ions can release and absorb H+ ions with carbonic acid?
Biocarbonate ions (HCO3)
92
Where does CO2 dissolve to form H2CO3?
Plasma
93
What group in haemoglobin join with H+ ions?
amino groups -NH2
94
What group in haemoglobin release H+ ions?
Carboxyl group -COOH
95
How is pH impacted during strenuous exercise?
pH falls
96
Why does pH fall during strenuous exercise?
CO2 is produced which increases H+ ions
97
What in the blood is sensitive to changes in pH?
Chemoreceptors
98
Where are these chemoreceptors located?
Carotid Artery and Aorta
99
Where are nervous impulses sent when fall of pH is detected?
Medulla in the brain
100
Where does the medulla then send more nervous impulses?
Inter-costal muscles and diaphragm
101
What happens when nervous impulses are sent to these muscles in the lung?
They contract more often and more forcefully
102
What happens to breathing with low pH?
Deeper and faster
103
What does the kidneys do if blood pH falls?
Excrete excess H+ ions
104
What collection of tests is used to determine blood pH?
Arterial Blood Gas Analysis
105
What artery is ABG usually carried out on?
Radial artery in the wrist
106
What is the blood analysed for during ABG?
pH
concentration CO2
concentration O2
107
What is a pH below 7.35 known as?
Acidosis
108
What is a pH above 7.45 known as?
Alkalosis
109
What are the 2 main categories of abnormal pH?
Malfunction of the respiratory system
Changes in level of hydrogen carbonate in blood
110
How is respiratory acidosis caused?
Lung disease such as asthma, pneumonia
Decreased breathing due to medications
Diseases affecting muscles or nerves of respiratory system
111
How is respiratory acidosis compensated?
The kidneys reabsorb more HCO3 to remove excess H+ ions from blood
112
What causes respiratory alkalosis?
Hyperventilation due to extreme anxiety, panic attacks, asthma attack or stress
Stroke
Pneumonia
Severe infection or fever
113
How is respiratory alkalosis compensated?
The kidneys reabsorb less HCO3 so less if removed from the blood
114
What causes metabolic acidosis?
Diabetes (ketoacidosis)
Severe diarrhoea
High levels of lactic acid due to severe over exercise
115
How is metabolic acidosis compensated?
Breathing rate increases to remove CO2 and therefore H+ ions from blood
116
What causes metabolic alkalosis?
Excessive vomiting
Overuse of diuretics
Overuse of alkaline drugs
117
How is metabolic alkalosis compensated?
Breathing rate decreases to retain CO2 and therefore H+ in the blood
