Chapter 3 - Endocrine System Flashcards

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1
Q

What are hormones?

A

Chemical substances produced in minute quantities by endocrine glands

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2
Q

Hormones are transported to target organs by:

A

blood

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3
Q

What do hormones influence?

A

They influence growth, development and activity of an organism

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4
Q

What happens to hormones after performing their functions?

A

They are destroyed in the liver and excreted by the kidneys

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5
Q

How do hormones affect the body?

A
  • Help in the delivery of baby out of the mother’s womb during childbirth
  • Result in the increase in height of a child
  • Prepare the body for ‘fight’ or ‘flight’ during dangerous encounters
  • Responsible for physical and emotional changes during puberty
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6
Q

Why must production of hormones must be carefully controlled?

A

When too much or too little hormones are produced, the organism will be adversely affected

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7
Q

What happens when there is too little thyroxine in a tadpole?

A

This will inhibit its grow into a frog

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8
Q

What happens when there is too much thyroxine in a tadpole?

A

This will turn it into the adult form too quickly, resulting in a tiny frog

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9
Q

Hormone production in the body is controlled by:

A
  • the nervous system

- certain chemical substances (hormones from other endocrine glands)

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10
Q

Where are hormones produced?

A

In endocrine glands

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11
Q

What happens to hormones after they are produced?

A

They are released directly into the blood from the endocrine glands

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12
Q

Feature of endocrine glands

A

Have an extensive network of blood vessels to transport hormones to their target organs

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13
Q

What are the two types of glands?

A

Endocrine glands and exocrine glands

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14
Q

What are endocrine glands?

A

Ductless glands that transport their secretions via the bloodstream

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15
Q

What are examples of endocrine glands?

A

Adrenal glands
Pituitary gland
Pancreas

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16
Q

What are exocrine glands?

A

Ducts present to transport secretions to target organs

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17
Q

What are examples of exocrine glands?

A

Sweat glands
Salivary glands
Pancreas

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18
Q

Pituitary gland: regulated by

A

Hypothalamus

- regulates the secretion of some pituitary hormones

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19
Q

Pituitary gland: hormone(s) secreted

A
Growth hormone (GH)
Antidiuretic hormone (ADH)
Thyroid-stimulating hormone (TSH)
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20
Q

Pituitary gland: special feature

A

Secretes hormones that control the functions of several other endocrine glands

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21
Q

Thyroid gland: stimulated by

A

Thyroid stimulating hormone (TSH)

- secreted by the pituitary gland

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22
Q

Thyroid gland: hormone(s) secreted

A

Thyroxine

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23
Q

Function of thyroxine

A
  • Controls metabolism rate and influences physical development
  • Exerts both short and long term effects in the body
24
Q

Adrenal glands: situated on

A

On top of each kidney

25
Q

Adrenal glands: stimulated by

A

The nervous system

26
Q

Adrenal glands: hormone(s) secreted

A

Adrenaline

27
Q

Pancreas: hormone(s) secreted

A

Pancreatic juice
- secreted by exocrine gland via pancreatic ducts
Insulin and glucagon
- secreted by Islet of Langerhans (endocrine)

28
Q

Function of insulin and glucagon

A

To control blood glucose levels

29
Q

Pancreas: special feature

A

Has both endocrine and exocrine functions

30
Q

Gonads: hormone(s) secreted

A

Oestrogen and progesterone
- secreted by ovaries (in females)
Testosterone
- secreted by testes (in males)

31
Q

Function of oestrogen

A

Controls the development of breasts and broadening of the pelvis

32
Q

Function of progesterone

A

Helps maintain a healthy pregnancy

33
Q

Function of testosterone

A

Causes deepening of voice and growth of facial hair

35
Q

What is the function of insulin?

A

DECREASES blood glucose concentration

36
Q

What are the effects of insulin?

A
  • Increases the rate of glucose uptake by cells
  • By making cell membranes more permeable to glucose
  • Stimulates the liver and muscle cells to convert glucose into glycogen for storage
  • Increases the oxidation of glucose during tissue respiration
37
Q

What are the effects of over-secretion of insulin?

A

Abnormally low blood glucose concentration

  • Symptoms includes hunger, rapid heartbeat and irritability
  • In severe cases, person may lapse into a coma or even die
38
Q

What are the effects of lack of insulin secretion?

A

Abnormally high blood glucose concentration

  • Tissue cells cannot utilise or store glucose
  • Symptoms includes weak body, continual weight loss and glucose present in urine
  • Could lead to diabetes mellitus disease
39
Q

How does diabetes mellitus occur?

A
  1. Insufficient insulin secretion to regulate blood glucose concentration
  2. Persistently high level of glucose in blood
  3. Kidneys are unable to completely reabsorb glucose in body
  4. Glucose is excreted in urine
40
Q

What are the signs of diabetes mellitus?

A
  • Constantly high blood glucose concentration
  • Presence of glucose in urine after a meal
  • Healing of wounds is slow and difficult
41
Q

What are the two types of diabetes?

A

Type I diabetes and type II diabetes

42
Q

What is type I diabetes?

A

Early-onset diabetes where insufficient or no insulin is production

43
Q

What is the treatment of type I diabetes?

A

Insulin injection

44
Q

What is type II diabetes?

A

Late-onset diabetes where insulin is produced but target cells do not respond well to insulin

45
Q

What is the treatment of type II diabetes?

A

Control of dietary intake and exercising

46
Q

What is the function of glucagon?

A

INCREASES blood glucose concentration

47
Q

What are the effects of glucagon?

A

Stimulates the following conversions:

  • Glycogen into glucose
  • Fats and amino acids into glucose
  • Lactic acid into glucose
48
Q

What is the main target organ of glucagon?

A

Liver

49
Q

What happens when there is low blood glucose concentration?

A
  1. Islets of Langerhans secrete glucagon
  2. More glucose is produced
  3. Increase in blood glucose concentration
50
Q

What controls the secretion of insulin and glucagon?

A

Controlled by negative feedback mechanisms

51
Q

What is the function of adrenaline?

A

Allows the body to respond quickly to sudden demands for energy

52
Q

When is adrenaline secreted?

A

Secreted in response to stress or excitement

53
Q

What happens when there is stress or excitement?

A
  1. Stimuli activate sensory neurons in the hypothalamus
  2. Adrenal gland is stimulated to produce adrenaline
  3. Adrenaline is carried in blood to target organs
  4. Target organs response to the short-term effect of adrenaline
54
Q

What are the effects of adrenaline?

A
  • Increases blood pressure and rate of heartbeat
  • Increases rate and depth of ventilation
  • Increases metabolic rate
  • Increases blood glucose level
  • Increases the rate of blood coagulation
  • Causes pupils to dilate
  • Contracts hair muscles, producing ‘goose pimples’
  • Constricts arterioles in skin
54
Q

What are the similarities between endocrine and nervous controls?

A

Both have the following components:

  • A detector that detects a stimulus
  • A signal or message that is transmitted
  • An effector (target organ that carries out the response)
55
Q

What are the differences between endocrine and nervous controls?

A
  • N: involves neurons. E: involves hormones
  • N: electrical and chemical transmission. E: chemical transmission
  • N: nerve impulses are transmitted by neurones. E: hormones are transmitted by the blood
  • N: rapid transmission and response. E: slower transmission and relatively slow-acting
  • N: often causes short-term effects. E: can cause long-term or short-term effects
  • N: voluntary or involuntary. E: always involuntary
  • N: usually localised response. E: usually widespread effects