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BIOLOGY > Homeostasis + Osmoregulation > Flashcards

Homeostasis + Osmoregulation Flashcards

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1
Q

What is Homeostasis?

A

Homeostasis is the maintenance of relatively constant internal conditions.

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2
Q

What three ‘types’ of mechanisms are there to maintain homeostasis?

A

Structural (Physical features that assist in tolerating changes), Physiological (Internal processes and mechanisms) and Behavioural (Behaviours or actions that keep organisms alive).

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3
Q

What is a tolerance limit?

A

A tolerance limit is the internal factors that need to be maintained for organisms to function correctly

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4
Q

What are some examples of tolerance limits?

A

Body temperature, water concentration, blood carbon dioxide concentration and blood glucose levels.

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5
Q

What is negative feedback?

A

Negative feedback occurs the initial response diminishes or reverses the original stimulus.

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6
Q

Explain the stimulus-response model.

A

The stimulus-response model is the pathway of nerve impulses. The stimulus is the variable internal or external factor. The receptors detect this stimulus. The transmission then relays the information to the effector. The effector starts a response after receiving the information. The response is the overall action that has occurred due to the initial stimulus, and the feedback is the response’s impact, whether positive or negative.

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7
Q

What is positive feedback?

A

Positive feedback is when the response reinforces the initial stimulus

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8
Q

What is the central nervous system? What does it do?

A

The central nervous system consists of the brain and spinal cord. Its role is to store, arrange and manage information.

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9
Q

What is the peripheral nervous system? What does it do?

A

The peripheral nervous system transmits information to and from the sensory receptors.

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10
Q

What is the difference between somatic and autonomic nerves?

A

Somatic nerves are voluntary responses, whereas autonomic nerves are involuntary.

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11
Q

What is the difference between sympathetic and parasympathetic?

A

The sympathetic nervous system activates the flight or fight response, and the parasympathetic nervous systems restores the body to a state of calm

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12
Q

What is a neuron? What does it do relating to homeostasis?

A

Neurons are responsible for sending and receiving neurotransmitters.

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13
Q

What are the three main components of a neuron?

A

Dendrites (receive impulses from receptors and transmit info to the cell body), A cell body (contains organelles), Axons (long extensions of the neuron, transmits information to other cells or effectors. The end of axons branch off into swellings where neurotransmitters are released from)

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14
Q

What is a sensory neuron?

A

A sensory neuron has a cell body joined by two long processes, the dendron and the axon.

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15
Q

What is an interneuron?

A

An interneuron only has short axons as they enable connectors between sensory and motor neurons.

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16
Q

What is a motor neuron?

A

A motor neuron has short dendrites and one long axon.

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17
Q

How do neurons transmit messages to specific destinations?

A

Through electrochemical impulses.

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18
Q

What is the synapse?

A

The small gap between neurons

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19
Q

What are some examples of neurotransmitters?

A

Acetylcholine, Norepinephrine, Dopamine, and Serotonin.

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20
Q

What are the five types of sensory receptors, and how do they differ?

A

Mechanoreceptor (the five senses), Photoreceptor (light), Thermorecptor (temperature changes), Chemoreceptor (changes in chemicals), and Nocirecptor (detects tissue damage and pain).

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21
Q

What is the tolerance limit for blood pH?

A

Blood pH is usually 7.4 but is maintained between 7.35 and 7.45.

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22
Q

What is the relationship between blood pH and carbon dioxide?

A

CO2 is transported in the bloodstream to the lungs and ultimately removed from the body through exhalation.

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23
Q

What is a hormone?

A

Hormones are chemicals produced by cells and carried by the blood to create effects in the rest of the body.

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24
Q

What produces hormones?

A

The endocrine glands

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25
Q

What are the three main classes of hormones?

A

Peptide and protein (short chains of amino acids (polypeptide) and proteins consisting of larger chains), amino acid-derived hormones (small molecules that are derived from amino acids tyrosine and tryptophan), lipid/steroid hormones (lipid-based hormones, derived from cholesterol)

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26
Q

What is the pituitary gland?

A

The pituitary gland is located at the brain’s base and controls all other endocrine glands. The pituitary gland produces oxytocin, antidiuretic, human growth hormone, follicle-stimulating, luteinising, and thyroid-stimulating hormone.

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27
Q

What is the thyroid gland?

A

The thyroid gland produces thyroxine which is responsible for stimulating metabolism and producing heat

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28
Q

How do the beta and alpha cells within the Islet of Langerhans differ?

A

When elevated blood levels are detected, insulin is released from beta cells from the Islet of Langerhans. When decreased blood glucose levels are detected, glucagon is released from the Islets of Langerhans alpha cells.

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29
Q

What does glucagon do?

A

Glucagon’s role is to prevent blood glucose levels from dropping too low. To do this, glucagon acts on the liver in several ways, stimulating the conversion of stored glycogen to glucose.

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30
Q

What does insulin do?

A

Insulin is a hormone our body makes to keep our blood glucose levels within the normal range. It is made by beta cells in the pancreas. Insulins’ main job is to move glucose from our bloodstream into the body’s cells to make energy.

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31
Q

What is diabetes?

A

Diabetes is a metabolic disorder where a person does not produce enough insulin, or their body does not respond appropriately to insulin.

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32
Q

What is it called when blood glucose decreases and increases?

A

Decreased blood glucose levels, known as hypoglycaemia, cause headaches, weakness, sleepiness, and dizziness. Increased blood glucose levels, known as hyperglycaemia, cause symptoms such as hunger, tiredness, thirst or blurred vision.

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33
Q

Explain type 1 diabetes.

A

Type 1 diabetes is an autoimmune disease where immune cells are activated to produce antibodies against the body’s insulin.

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34
Q

Explain type 2 diabetes.

A

Type 2 diabetes is a condition that develops over time and is mostly attributed to poor lifestyles and diet.

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35
Q

What does thyroxine do? What produces it?

A

Thyroxine is a hormone produced by the thyroid gland and is then secreted into the circulatory system. It acts on most cells in the body to regulate metabolism by increasing the basal metabolic rate

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36
Q

What occurs during a decrease in thyroxine versus and increase?

A

When there is a lack of thyroxine, it will result in sleepiness, decreased appetite and slow thoughts and speech. Too much thyroxine will cause a rapid heart rate, shortness of breath, and increased appetite.

37
Q

What is osmoregulation?

A

The maintenance of constant osmotic pressure in the fluids of an organism by the control of water and salt concentrations.

38
Q

What does the hypothalamus do during the control of homeostasis?

A

The hypothalamus responds to stimuli, passing transmissions to the receptors and effectors.

39
Q

What does the antidiuretic hormone do?

A

The antidiuretic hormone causes the kidneys to release less water. When this occurs, there is an increase in aquaporins in the collecting ducts in the kidney’s nephrons. As a result, a lower volume of urine is produced.

40
Q

What mechanism is adrenaline responsible for?

A

The fight or flight response

41
Q

What happens during an increase in adrenaline?

A

Increased heart rate, increased blood pressure, dilation of pupils, increased metabolic rate and increased blood flow to muscles.

42
Q

What mechanisms produce and conserve heat in animals?

A

Erection of feathers/hair, restricted blood flow to the surface of the skin, shivering and increased metabolic rate

43
Q

What mechanisms reduce heat in animals?

A

Flattened hair/feathers, metabolic rate reduced, and sweat glands increase

44
Q

What mode of transmission does sweating use?

A

Nervous

45
Q

What mode of transmission does Thyroxine use?

A

Hormonal

46
Q

What mode of transmission do sphincter muscles use?

A

Nervous/Hormonal

47
Q

What happens when a decrease in blood temperature occurs?

A

Shivering, vasoconstriction and an increased metabolic rate

48
Q

What happens during an increase in blood temperature?

A

Sweat glands become active, evaporative cooling, vasodilation and decreased metabolic rate.

49
Q

What is the nervous system, and what does it do?

A

It controls much of what you think and feel and what your body does. It allows you to do things like walk, speak, swallow, breathe and learn. It also controls how the body reacts in an emergency.

50
Q

What is the endocrine system, and what does it do?

A

Endocrine glands release hormones into the bloodstream. This lets the hormones travel to cells in other parts of the body.

51
Q

Compare the nervous and endocrine systems.

A

The endocrine system uses chemical signaling (hormones, produced by glands) while the nervous system uses electrical signaling (neural impulses).

52
Q

What are four factors that humans can respond to.

A

Temp, pH, osmotic pressure, glucose concentration

53
Q

What are four factors that humans can respond to?

A

Temp, pH, osmotic pressure, glucose concentration

54
Q

Give an example of a structural, behavioural and physiological response organisms may have.

A

Structural: development of chemoreceptors to detect CO2 levels
Behaviour: seeking shade, curling into a ball
Physiological: Hairs erecting, shivering, increasing metabolic rate

55
Q

Explain “ The concept of tolerance levels can be applied to homeostasis”

A

Certain variables need to be maintained between upper and lower limits; the tolerance range for efficient functioning.

56
Q

What are two reasons why humans need to maintain the correct concentration of CO2 within their blood?

A
  1. CO2 acts as a breathing stimulus
  2. A decrease in CO2 would alter the pH of the blood
57
Q

Name two mechanisms used to transmit information in the stimulus-response model

A

The endocrine and nervous system

58
Q

What factors could cause a fall in blood glucose levels?

A

Fasting, heavily exercising, not recently eaten

59
Q

What factors could cause a rise in carbon dioxide concentration in blood?

A

Heavily exercising

60
Q

What factors could cause a high blood solute concentration?

A

Not drinking enough water

61
Q

Explain how the maintenance of blood glucose levels results from negative feedback.

A

The maintenance of the tolerance levels occurs as a result of homeostatic processes. The response feeds back to the initial stimulus and reverses it

62
Q

Name an example of positive feedback in humans.

A

Breast feeding

63
Q

Why is positive feedback not as common as negative feedback?

A

Positive feedback is not common as it does not keep variables within tolerance limits.

64
Q

Sweating can reduce blood temperature, but it also impacts another variable. What is this variable?

A

Osmotic pressure

65
Q

Describe an Inter Neuron

A

Cell body, short dendrites, short axon

66
Q

Describe a Motor Neuron

A

Cell body, short dendrites, long axon

67
Q

Describe a Sensory Neuron

A

Cell body, long dendrites, short axon

68
Q

What enables a nerve impulse to reach an adjacent neuron?

A

Vesicles in the presynaptic knob are stimulated by the entry of calcium ions to release neurotransmitters.

69
Q

What are the CNS and the PNS?

A

CNS stands for “central nervous system” and refers to the brain and spinal cord. PNS stands for “peripheral nervous system” and refers to all other nerves in the body.

70
Q

Explain why sensory neurons and interneurons have different structures.

A

Sensory neurons have dendrites adapted to detect or sense information, and long axons transmit information. Interneurons have short axons as they only need to connect from one neuron to another.

71
Q

Name three components of a neuron

A

Dendrite, cell body and axon

72
Q

How does the Dendrite structure suit its function?

A

A dendrite is an extension that acts as a sensory receptor and will respond to stimuli.

73
Q

How does the Cell body structure suit its function?

A

A cell body contains organelles.

74
Q

How does the Axon structure suit its function?

A

An axon is an extension of a nerve cell to conduct impulses over long distances.

75
Q

What is a reflex arc?

A

The nerve pathway involved in a reflex action, including a sensory nerve and a motor nerve with a synapse between.

76
Q

What is the difference between the CNS and the PNS?

A

CNS stores and manages information, the PNS relays information to and from the CNS.

77
Q

What does a mechanoreceptor detect?

A

mechanoreceptors respond to touch or pressure.

78
Q

What are neurotransmitters?

A

A chemical substance which is released at the end of a nerve fibre by the arrival of a nerve impulse

79
Q

Name two ways that the nervous and hormonal systems communicate similarly.

A

Both involve chemicals at some stage. And enable messages to be relayed to target tissues

80
Q

Name two ways that the nervous and hormonal systems communicate differently.

A
81
Q

Give one example of homeostasis that involves nerve transmission.

A

The control of CO2 levels in the blood only involves nerve transmission

82
Q

Give one example of homeostasis that involves hormone transmission.

A

The control of blood glucose only involves hormone transmission with the hormones insulin and glucagon

83
Q

Give one example of homeostasis involving the nervous and endocrine systems working together.

A

The nervous and endocrine systems work together in the control of blood temperature

84
Q

How does metabolic rate control blood temperature?

A

Increased metabolism releases energy as a by-product. This is used to heat the body.

85
Q

How does vasodilation control blood temperature?

A

Vasodilation increases the blood flow to the surface of the skin therefore increasing heat loss.

86
Q

How does sweating control blood temperature?

A

Sweating causes evaporative cooling to occur in order to lower body temperature.

87
Q

How do increased levels of thyroxine control blood temperature?

A

Thyroxine increases the activity of mitochondria and therefore increases the metabolic rate.

88
Q

How do negative feedback and homeostatic control of blood temperature correlate?

A

This mechanism maintains blood temperature around 37 degrees between its narrow tolerance limits. The responses reverses the stimulus

BIOLOGY (2 decks)

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