GHM L2 Flashcards

1
Q

Describe the position of the hypothalamus

A

Located below the thalamus, between the midbrain + optic chiasm

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2
Q

What is the thickness of hypothalamus?

A

3-4mm thick
Size of almond

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3
Q

What are the inputs of hypothalamus?

A
  1. Somatosensory
  2. Taste
  3. Smell
  4. Limbic system
  5. Retina
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4
Q

What factors does the hyothalamus sensor?

A

Hormones
BP
Temp

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5
Q

What are the functions of hypothalamus?

A

Regulation of body temp

Regulation of autonomic nervous system

Regulation of emotional responses

Regulartion of hunger

Regulation of growth

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6
Q

Give 2 nuclei of hypothalamus and state their functions

A
  1. PVN: Paraventricular nucleus. Responsible for
    -Stress reponse
    -Food intake
    -Thyroid regulation
    -Osmoregulation

SON: Supraoptic nucleus. Responsible for
-Blood pressure
-Osmoregulation
-Lactation
-Parturition

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7
Q

Give 2 hormones produced by the hypothalamus

A
  1. Liberins - releasing hormones
  2. Statins - inhibiting hormones
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8
Q

How are releasing + inhibiting hormones transported from hypothalamus to anterior pituitary gland?

A

They are transported directly only to anterioir pituitary gland via hypothalamic hypophyseal portal vein

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9
Q

What is the role of releasing hormones produced by hypothalamus?

A

Control of other hormones by stimulating release.

“turn on”

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10
Q

What is the role of inhibiting hormones produced by hypothalamus?

A

Control of other hormones by inhibiting release

“turn off”

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11
Q

Where is the pituitary gland located?

A

Located in hypophyseal fossa in sphenoid bone
Pea sized

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12
Q

Describe the structure of the pituitary gland

A

Pituitary - hypophysis

Anterior pituitary gland - ADENOHYPOHISIS

Posterioir pituitary gland NEUROHYPHISIS

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13
Q

Describe the structure of the anterioir pituitary gland?

A

The adenohyphysis

  1. Pars tuberalis
  2. Pars intermedia
  3. Pars distalis
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14
Q

Describe the structure of the posterioir pituitary gland?

A
  1. Pars nervosa
  2. Infundibular stalk
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15
Q

Sate the function of pars tuberalis

A

Reception for endocrine signals

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16
Q

State the function of pars intermedia

A

Sheath between the anterioir + posterior pituiatry gland. Small in humans

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17
Q

State the function of pars distalis

A

Hormone production

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18
Q

State the function of pars nervosa

A

Storage of OT (oxytocin) and ADH

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19
Q

State the function of infundibular stalk

A

Connecting bridge between hypothalmus and hypophysis (pituitary gland)

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20
Q

What are the 5 types of hormone secreting cells in the anterioir pituitary gland (adenohypohysis) and what hormones do they secrete?

A
  1. Somatotropes - growth hormone - bone + muscle tissue
  2. Lactotropes - Prolactin - breasts
  3. Gonadotropes - FSH, LH - ovaries, testes
  4. Corticotropes - adrenocorticotropin - adrenal cortex
  5. Thyrotropes - thyroid stimulating hormone - to the thyroids
21
Q

Which two hormones are secreted by cells in the posterior pituitary gland?

A

Oxytocin - breasts
ADH - kidneys

22
Q

Thyroid disorders

A

Change in conc of thyroid hormones (T3 and T4). This affects metabolism, which affects activity levels.

Usually caused by tumours

Can lead to:

Hypothyrodism - Hashimoto’s thyrodism
Hyperthyrodism - Grave’s dosease
GOITRE

23
Q

Give 3 examples of adrenocorticotropins

A

CORALDA -COR-ALD-A

Adrenocotrical hormones:

  1. Cortisol
  2. Aldosterone
  3. Androgens
24
Q

State the function of cortisol

A

-Carbohydrate metabolism
-Stress response

25
Q

State the function of aldosterone

A

Salt regulation
Water homeostasis - osmoregulation

26
Q

State the function of androgen

A

Male seconday sex characteristics
Virilization in females

27
Q

Describe the corticotropin releasing hormone pathway

A

Corticotropin releasing hormone is produced in the paraventricular nucleus in the hypothalamus.

It is relased into the anterior postiuitary gland.

Here, it stimulates corticotropes to release adrenocorticotropins

Adrenocotricotropins are secreted in adrenal cortex where they stimulate production of
-cortisol
-aldosterone
-androgen
-glucocorticoids
-mineralcorticoids

28
Q

Describe the physiological actions of cortisol

A

Cortisol is released in a diurnal rythm.
This is good for seasonal breeding of animals

Cortisol - glucose metabolism. It increases synthesis of enzymes involved in gluconeogenesis in liver - anabolic

It increases break down of fat + muscle tissue to release energy - catabolic

Net effect - higher levels of glucose (hyperglycemia)

Peak of cortisol releaese: 6-8 am
Lowest - midnight
Fluctuates after a meal

29
Q

Describe “Cushing’s Disease” and state the causes

A
  • Too high cortisol levels
  • Adrenal tumour, pituitary tumour, lung tumour

LAP

LUNG ADRENAL PITUITARY
LAP IS A CUSHION

30
Q

How does aldosterone regulate salt levels in the human body?

A

Aldosterone is a primary mineralcorticoid

It controls the conc of Na+ + K+ in the epithelial cells, it also controls movement of Na
+ + K+ out of TARGET epithelial cells

It stimulates active transport of Na+ into epithelial cells of distal convuluted tubules

Aldosterone increases the number of Na+ channels in the apical membrane

Aldosterone also increases the number of Na/K ATPase molecules

31
Q

State 2 aldosterone disorders

A
  1. Addision’s disease
  2. Hyperaldosteronism
32
Q

State a cause of Addision’s disease

A
  1. Inadequate amount of mineralcorticoid - aldosterone
33
Q

State symtoms/effects of Addision’s disease

A
  1. Low BP
  2. Hyperpigmentation of skin
34
Q

State a cause of hyperaldosteronism disease

A

Too much aldosterone

35
Q

State symtoms/effects of hyperaldosteronism

A
  1. High BP
  2. Hypopigmentation of skin
36
Q

Where is growth hormone produced?

A

Somatotropes in anterioir pituitary gland

37
Q

Explain the functions of growth hormone

A
  1. Direct function

Diabetigenic
Opposes insulin action
Lypolytic in fat
Gluconeogenic in muscle

Indirect Function

Stimulates release of IGF-1 FROM LIVER, this leads to growth of bone tissue, lipolysis, protein synthesis in muscle

38
Q

Describe what happens when we have too much growth hormone

A

ACROMEGALY
overgrowth of bony areas

CAUSED BY anterior pituitary tumor

39
Q

Describe what happens when we have too little growth hormone

A

Dwarfism in infants

40
Q

Describe the control of the posterior pituitary gland

A

Neurones which control posterior pituitary found in the

  1. PVN
  2. SON

These neurones send neural projectoons down infundibular stalk

Cause POSTERIOIR PITUITARY (PARS NERVOSA) TO Secrete ADH, oxytocin directly into blood stream

41
Q

Describe the effect of high ADH

A
  • Collecting ducts more permeable to water. therefore, HYPEROSMOTIC urine
42
Q

What factors determine ADH release

A

Blood vol
detected by osmoreceptors in hypothalamus - they detect osmolarity of blood

43
Q

State the name of the carrier protein which transports ADH to posterior pituitary

A

NEUROPHYSIN II

44
Q

Where are ADH receptors found?

A
  • Kidney
  • Pituitary
  • Brain
  • Blood vessels
    -Platelets
    -Gonads
    -Tumours
45
Q

What are the 3 type of ADH receptors?

A

V1a, V1B V2

-G protein coupled receptors

46
Q

Where is oxytocin synthesised?

A

PVN, SON (hypothalamus)

47
Q

State the name of the carrier protein which transports oxytocin to posterior pituitary

A

Neurophysin I

48
Q

Functions of oxytocin

A

-Lactation
-Partuition
-Maternal behaviour