Homeostasis and Thermoregulation Flashcards

1
Q

Homeostasis

A

Maintenance of internal environment

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2
Q

Feedback system consists of a

A
Stimulus
Receptor
Modulator
Effector
Feedback
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3
Q

Negative Feedback Loops

A

Where the response causes the stimulus to change in a direction opposite to that of the original stimulus

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4
Q

Positive Feedback

A

The response to stimulus reinforces and intensifies the stimulus

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5
Q

Thermoregulation

A

Human body Temperature

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6
Q

Heat Gain

A
  1. Internal
    - Metabolic rate
  2. External
    - Radiation or conduction
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7
Q

Heat Loss

A
  1. Internal
    - Evaporation of water from skin and lungs
    - Warm air breathed out
    - Warm urine and faeces
  2. External
    - Radiation, conduction and convection
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8
Q

Conduction

A

Transfer of heat via direct contact with another object

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9
Q

Convection

A

Transfer to heat to air around the body

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10
Q

Radiation

A

Transfer to heat without contact

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11
Q

Evaporation

A

Transfer of heat through evaporation of liquid to gas

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12
Q

Temperature Tolerance

A
  1. Heat stroke (body temp rises by regulatory mechanisms not working)
  2. Heat Exhaustion (result of extreme sweating and vasodilation)
  3. Hypothermia (cored body temp falls below 33 degrees)
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13
Q

Temperature Receptors

A
  1. Peripheral thermoreceptors in skin and mucous membranes

2. Central Thermoreceptors in hypothalamus

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14
Q

Thermoregulation Short term Keeping Cool

A

Stimulus
Increase in body temp

Receptor
Thermoreceptors (central and peripheral)

Modulator
Hypothalamus

Effector
Sweat Glands
Blood Vessels
Cerebrum

Response
Increase sweating
Vasodilation
Behavioural

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15
Q

Thermoregulation Long Term Keeping Cool

A

Stimulus
Increase body temp

Receptor
Thermoreceptors

Modulator
Hypothalamus

Effector
Thyroid

Response
Decrease metabolic rate, which decreases heat production

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16
Q

Thermoregulation Long Term Keeping Warm

A

Stimulus
Decrease in body temperature

Receptor
Thermoreceptors (central only)

Modulator
Hypothalamus

Effector
Thyroid

Response
Increase Metabolic rate which increases heat production

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17
Q

Thermoregulation Short Term Keeping Warm

A

Stimulus
Decrease in body temperature

Receptor
Thermoreceptors (central and peripheral)

Modulator
Hypothalamus

Effector
Skeletal muscle
Blood vessels of skin
Cerebrum
Adrenal Medulla
Response
Shivering
Vasoconstriction of BV
Behavioural
Adrenaline, Noradrenaline
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18
Q

Osmoregulation in blood

A
  1. Water is lost from the blood resulting in blood having a higher osmotic pressure
  2. High osmotic pressure is detected by osmoreceptors in the hypothalamus
  3. Water then moves from the intracellular fluid into the plasma via osmosis
  4. Resulting in lowering the concentration of water in the intracellular fluid which then causes water to leave the cells resulting in the cells to shrivel and shrink
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19
Q

Antidiuretic Hormone

A

ADH is produced by the hypothalamus and released by the posterior lobe of the pituitary

ADH controls the permeability of the walls of the distal convoluted tubule and the collecting duct

ADH concentration is high this results in the tubules being more permeable to water

This results in water enabled to be reabsorbed

Water leaving the tubule decreases volume of filtrate and increases the concentration of contents

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20
Q

Aldosterone

A

The Adrenal cortex also secretes aldosterone to increase amount of sodium reabsorbed into blood and increase the amount of potassium excreted into urine

Water is reabsorbed along with sodium so aldosterone can also regulated water content

ADH and Aldosterone work together to regulate water

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21
Q

Dehydrated Feedback loop

A

Stimulus
Increase in Osmotic pressure

Receptor
Osmoreceptors

Modulator
Posterior pituitary

Effector
DCT and CT of Nephron

Response
Increase permeability, which increases reabsorption of water into the blood

22
Q

Thirst Feedback Loop

A

Stimulus
Increase osmotic pressure

Receptor
Osmoreceptors in the thirst centre

Modulator
Cerebrum

Effector
Alimentary canal

Response
Increase absorption of water into the blood

23
Q

Dehydration

A
Symptoms:
Severe thirst
Low Blood pressure
Dizziness
Headache
24
Q

Water Intoxication

A
Symptoms:
Lightheadedness
Headache
Vomiting
Might Collapse
25
How is breathing controlled?
Our diaphragm and intercostal muscles receive stimulation from nerves to contract
26
Control of Breathing
Breathing is controlled by the respiratory centre in the medulla oblongata
27
What effects breathing rate
Oxygen, Carbon Dioxide and Hydrogen Ions Carbon Dioxide concentrations affect hydrogen ion concentrations due to when co2 dissolves in water it forms carbonic acid which breaks down to form hydrogen ions
28
Chemoreceptors
Peripherally --> Aortic and Carotid bodies Centrally --> medulla oblongata
29
Increase CO2, H+ and decrease in pH feedback loop
Stimulus Increase CO2 Increase H+ ions Decrease in pH Receptor Chemoreceptors in aortic and carotid bodies Modulator Respiratory centre in medulla olbongata Via Phrenic and Intercostal nerves Effector Diaphragm and intercostal muscles Response Increase rate and depth of breathing = Decrease CO2 Concentration
30
Decrease CO2, H+ and increase pH
Stimulus Decrease CO2 Decrease H+ ions Increase pH Receptor Chemoreceptors in aortic and carotid bodies Modulator Respiratory centre in medulla oblongata VIA PHRENIC AND INTERCOSTAL NERVES Effector Diaphragm and intercostal muscles Response Decrease rate and depth of breathing = Increase CO2 concentration
31
Holding Breath
CO2 will build up This stimulate the inspiratory centre to stimulate the inspiratory muscles to take a breath
32
Hyperventiliation
It provides more O2 than needed and removes more CO2 Low CO2 = no urge to breathe This increases both breathing rate and depth of breathing
33
Exercise
Requires a lot of O2 and produces a lot of CO2 This increases breathing rate and depth of breathing
34
Regulating Blood Sugar
= the amount of Glucose in the blood
35
The Liver
Glucose in the blood travels straight to the liver via the hepatic portal vein
36
The Liver enables Glucose to:
Be removed and to provide energy for liver functioning Be removed and converted into glycogen for storage
37
Storing Glucose
Liver stores glucose as glycogen through a process called glycogenesis which is stimulated by insulin (secreted by the pancreas)
38
Using Glycogen
Glycogen is converted to glucose via glycogenolysis which is stimulated by glucagon
39
Pancreas
Contains hormone secreting cells known as islets of langerhan Alpha - secretes glucagon Beta - secretes insulin
40
Insulin in Pancreas
1. Causes increased uptake of glucose from the blood 2. Promotes the conversion of glucose to glycogen 3. Increases protein synthesis
41
Glucagon in Pancreas
1. Causes an increase in blood sugar 2. Stimulates glycogenolysis 3. Stimulates liver to produce new sugar molecules from fats and amino acids through gluconeogenesis
42
Adrenal Cortex
Secretes Glucocorticoids from the adrenal cortex which is stimulated by the adrenocorticotropic hormone from the anterior lobe of the pituitary gland It regulates carbohydrate metabolism to make sure there is enough energy for the cells
43
Adrenal Medulla
Secretes Adrenaline and Noradrenaline
44
Adrenaline and Noradrenaline
Increase blood sugar levels by stimulating the production of lactic acid from glycogen in muscle cells
45
Glucose
Simplest form of sugar
46
Glycogen
Stored form of glucose
47
Insulin
Decreases of blood glucose levels
48
Glucagon
increase of blood glucose level
49
Glycogenesis
Process of creating glycogen from glucose
50
Glycogenolysis
Process of creating glucose from glycogen
51
Lipogenesis
Creates fats from glucose in adipose tissue
52
Gluconeogenesis
Creating new glucose molecules from lipids and amino acids