Endocrine System Flashcards

1
Q

How does the endocrine system regulate homeostasis ?

A

By slow, long-lasting chemical signalling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What do hormones secreted from glands act on?

A

target organs via circulatory system.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What does the endocrine system need to be activated by ?

A

The nervous system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the 2 different mechanisms that glands function through ?

A

1 - ENDOCRINE
2. EXOCRINE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Where does the endocrine secrete hormones snd what’s its target ?

A
  • Secretion into BLOOD
  • Action on distant target
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Where does the exocrine mechanisms secrete hormones ?

A

Secretion through duct to skin or into lumen outside body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Whats the endocrine system scheme function ?

A

1) sense internal change
2) Integrate sensory information
3) Respond by acting on other body systems.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What do glands release hormone in response to ?

A

Internal change

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the hypothalamus ?

A

Brain area with various physiological functions important for maintaining homeostasis by linking nervous and endocrine systems

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are 3 functions of the hypothalamus ?

A

1- Integrates sensory input
2- Coordinates appropriate physiological responses
3- Regulates hormone release from pituitary gland and other glands all over body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How are hormones classified ?

A

According to function and structure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Whats a tropic and non tropic hormone ?

A

TROPIC HORMONE -
-Regulates production / secretion of another hormone in a gland

NON-TROPIC HORMONE -
- Has a direct effect on target organ

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are 3 structures of hormones ?

A

PEPTIDE - Most hormones are amino acids
AMINES - Derived from the amino acid tyrosine
STEROIDS - Derived from the lipid cholesterol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How are peptides released into the blood ?

A

1) Peprohormone precursor is translated and packaged into vesicles
2) PEPROHORMONE - PROHORMONE - HORMONE
3) Hormone packaged into secretory vesicles and stored in cytosol
4) Vesicles fuse with plasma membrane and release hormone into blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How is the hormone amine released into the blood ?

A

1- Synthesised from the amino acid tyrosine by specific enzymes
2- Packaged into secretory vesicles and stored until release
3- Vesicles fuse with plasma membrane and release hormone into blood.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the 3 different ways that catecholamines are synthesised, stored and released ?

A
  1. Dopamine
  2. Noradrenaline
  3. Adrenaline
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How is steroids synthesised, stored and released ?

A

1- Synthesised from the lipid cholesterol by specific enzymes
2- diffuse across plasma membrane into blood once synthesised
3- Can be converted into different hormones once in blood or at target

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Via what pathways does cholesterol give rise to many hormones ?

A

Via several enzymatic synthesis pathways.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What does the way a hormone is transported through the circulation depend on ?

A

Their solubility characteristics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What hormones are water-soluble and where are they located ?

A
  • Peptide, some amines
  • FREE in blood or binding to plasma proteins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What hormones are lipid-soluble and where are they located ?

A

-Steroid, some amines
- Bound to plasma proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

in what location do hormones circulate in the blood ?

A

The whole body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Explain how hormones only have specific effects ?

A

They only act in certain organs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Explain how hormones induce a response within a cell ?

A

Hormones bind to a specific RECEPTOR on cells in target organs. Hormone binding to its receptor induces a response within cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What are the two types of hormone receptors ?

A

Membrane receptors
Internal receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What are membrane receptors and what do they bind ?

A
  • GPCR or kinase-linked
  • bind peptides, catecholamines, or some steroids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Where do hormones bind on membrane receptors ?

A

Hormone binds to receptor on outside of plasma membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What responses does binding on membrane receptors cause ?

A

-Enzyme activation
- Change in protein synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What hormones bind to internal receptors ?

A

Most steroids, thyroid hormone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What internal receptor do hormones bind to ?

A

Cytosol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

How does hormone-receptor complex induce a response and what does it cause ?

A

By binding to DNA it causes protein synthesis to increase and decrease

32
Q

How is the speed different in neural responses than hormone ?

A

Hormone responses are much more slower and prolonged than neural responses

33
Q

What are the 4 different mechanisms that tightly regulate levels of hormones in circulation ?

A
  1. Secretion
  2. Activation
  3. Binding to plasma proteins
  4. Removal from circulation
34
Q

Whats the most important mechanism for controlling hormone levels ?

A

Negative feedback keeps hormone levels within a narrow range around a set-point.

35
Q

How does neuroendrocine reflexes regulate hormone secretion ?

A

Produce sudden increase in hormone secretion in response to a stimulus detected by nervous system.

36
Q

Give 2 other ways that the body can regulate hormone secretion ?

A
  1. External stimulus
  2. Internal stimulus
37
Q

What are the 3 different rhythms of hormones over time ?

A
  1. DIURNAL / CIRCADIAN RHYTHM
    - Regular change in daily hormone levels
  2. MONTHLY RHYTHM
    - female gonadal hormones
  3. ANNUAL RHYTHM
    - Mating
    - Hibernation
38
Q

What occurs to most hormones during metabolism in the liver , where are 3 other places this can occur ?

A

Most hormones are inactivated by metabolism in liver but some are also metabolised in kidney, blood and cells

39
Q

How can plasma proteins affect hormone levels ?

A

Plasma proteins that bind to hormones in blood are synthesised in liver and can also be metabolised, which indirectly affects hormone levels.

40
Q

How are most inactive metabolites excreted ?

A

In urine

41
Q

How can liver or kidney disease alter hormone levels ?

A

Liver or kidney disease can alter hormone levels due to effects on hormone / plasma protein metabolism and hormone excretion.

42
Q

How does being soluble in water affect hormones ?

A

Water soluble hormones are easily targeted by enzymes in blood and tissue for metabolism

43
Q

How does hormones being soluble in lipids affect metabolism ?

A

Lipid-soluble hormones are bound to plasma proteins and less easily targeted for metabolism or excreted.

44
Q

How can lipid soluble hormones increase their water solubility and reduce binding to plasma proteins ?

A

Undergo a series of enzymatic steps to increase their water solubility and reduce binding to plasma proteins

45
Q

What is hormone response proportional to ?

A

The number of receptors it binds to

46
Q

What is receptor down regulation ?

A

A decrease in receptor number in response to chronic elevation of hormone levels

47
Q

What does internalisation of hormone receptor complex reduce ?

A

Reduces receptor levels and can also allow for metabolism of hormone by cells.

48
Q

How do endocrine disorders come about ?

A

Mainly due to abnormal hormone secretion but can also result from abnormal responsiveness to hormone with normal hormone levels

49
Q

What is hyposecretion ?

A

Is a decrease in secretion of a hormone by a gland or of a topic hormone

50
Q

How are endocrine disorders treated ?

A

Mainly treated with hormone replacement

51
Q

What is the endocrine disorder hypersecretion ?

A

Is an increase in secretion of a hormone by a gland ( primary ) or of a tropic hormone ( secondary )

52
Q

What is hypersecretion caused by ?

A

Caused by tumour, abnormal antibody mimicking hormone, synthetic hormone

53
Q

What is hyper secretion treated by ?

A

Treated by removing tumour or medicines that reduce hormone synthesis or secretion.

54
Q

How can chemicals disrupt the endocrine system ?

A

-Chemicals made by humans such as pesticide released as sewage or industrial waste into water sources.
–Chemical structures are similar to hormones and can disrupt endocrine control of neural and behavioural maturation of animals
-Many can mimic or block effects of gonadal hormones and so can alter sexual development and differential of brain in animals

55
Q

What are some regular variation I’m physiology and behaviour that oscillate ?

A
  1. Heart rate
  2. Breathing
  3. Body temp
  4. Hormone secretion
  5. Excretion
56
Q

What is an endogenous rhythm and an example ?

A
  • generated internally
  • Self- sustaining
    e.g Body temp
57
Q

What is an exogenous rhythm and an example ?

A

-Generated by external environment
- depends on external environment
- Barnacle cirri

58
Q

What does it mean if the biological rhythms are circadian ?

A

Means many biological rhythms are around a day

59
Q

What does diurnal, nocturnal and crepuscular ?

A

DIURNAL - day
NOCTURNAL - night
CREPUSULAR - Dawn and dusk

60
Q

Give examples of behavioural patterns of activity that are subject to natural selection for diurnal, nocturnal and crepuscular animals ?

A
  • Diurnal predators with goof eyesight
  • Nocturnal prey animals avoiding predators
  • crepuscular animals have high food availability
61
Q

What are glucorticoids ?

A

Hormones involved in energy mobilisation.

62
Q

When is glucorticoids at peak level and how does it differ for cortisol ( most mammals ) and corticosterone ( rodents ) ?

A

Peak level is when waking up to prepare for activity
CORTISOL - Peak levels in morning
CORTICOSTERONE
- Peak levels in evening

63
Q

What is a tidal rhythm and what marine organisms have this ?

A

its a 2 day circulation and
-crustaceans
- Mollusks
-fish
-Insects

64
Q

What is circannual rhythms and 3 examples ?

A

Occurs annually around a year
- MATING
- HIBERNATION
- MIGRATION

65
Q

What does a biological clock do ?

A

Maintains endogenous rhythms independently of external environment

66
Q

What is ZEITGEBER ?

A

External cues which entrain biological rhythms

67
Q

What do experiments in mammals living in constant light or dark show the endogenous circadian rhythm is ?

A

25 hours

68
Q

What is the suprachiasmatic nucleus ?

A

Is the master clock in mammals

69
Q

What is the rhythm of neuronal activity maintained by ?

A

Clock genes

70
Q

What does self-activation of clock genes result in ?

A

In translation of clock proteins which accumulate in cytosol of suprachiasmatic nucleus neutrons

71
Q

What does high clock proteins levels act on ?

A

on nucleus to signal an end to further translation

72
Q

What does the suprachiasmatic nucleus synchronise the circadian rhythm with ?

A
  • RETINA
  • PINEAL GLAND
73
Q

Explain how the retina can activate clock genes ?

A

1- Light entrains the circadian rhythm to 24 hours
2- light activates photoreceptors in retina
3- certain photoreceptors activate clock genes in neurone of suprachiasmatic nucleus

74
Q

What does the pineal gland do when receives light indirectly from suprachiasmatic nucleus and at what levels in night and day is it involved in circadian rhythm ?

A

controls rhythmic production and secretion of melatonin hormone
involbed in circadian rhythm
NIGHT - High levels
DAY - LOW LEVELS

75
Q

How does melatonin levels alter as changing day lengths change over a year ?

A
  • Increase as days shorten
  • Decrease as days lengthen
76
Q

What does an animal contain if light is able to penetrate skull and directly activate pineal gland ?

A

Contains light-sensitive cells that do not depend on retinal input.