hypothalamus and pituitary

Question 1

what makes up the endocrine system?

Answer 1

the endocrine system consists of ductless glands that secrete into the blood.

Question 2

what do endocrine glands secrete?

Answer 2

hormones

Question 3

what is a hormone?

Answer 3

A compound that is secreted by one cell and travels through the circulatory system to affect the activities of cells in another part of the body

Question 4

what processes does the endocrine system control?

Answer 4

processes that require durations rather than speed.

Question 5

what does the endocrine system play a role in?

Answer 5

Important in maintaining homeostasis and other functions such as growth and reproduction

Question 6

what is endocrine action?

Answer 6

mediators released into blood to have action at distant cells

Question 7

what is paracrine action?

Answer 7

mediators released to have effects on neighbouring cells

Question 8

what is autocrine action?

Answer 8

mediators released to have effects on the same cell

Question 9

what are hormones?

Answer 9

chemical messenger secreted into blood to act on distant target cells

Question 10

what are neurohormones?

Answer 10

hormone released by neurons.

Question 11

what are some examples of neurohormones?

Answer 11

ADH, Oxytocin

Question 12

what are autacoids or local hormones?

Answer 12

chemical messenger that have paracrine action

Question 13

examples of autacoids?

Answer 13

histamine, Ecosanoids

Question 14

what are neurotransmitters?

Answer 14

chemical messenger released from the nerve terminals at the synaptic sites in response to action potential

Question 15

what do neurotransmitters do?

Answer 15

they act locally on the post synaptic site on adjoining target cells which may be muscle, gland or another neuron

Question 16

what are neuromodulators?

Answer 16

Chemical messenger which act on neuron at non synaptic sites to bring changes in the nerve cell.

Question 17

what are some of the major endocrine glands?

Answer 17

pineal
hypothalamus 
pituitary 
thyroid 
parathyroid
thymus
adrenal
pancreas
ovary and testes

Question 18

what are the 3 main categories of hormones?

Answer 18

peptides and protein
steroids
derivatives of amino acid tyrosine

Question 19

what are some examples of peptides and protein hormones?

Answer 19

Pituitary hormones, insulin, glucagon, parathormone

Question 20

which steroid hormones does the adrenal cortex secrete?

Answer 20

cortisol and aldosterone

Question 21

which steroid hormones do the ovaries and the placenta secrete?

Answer 21

oestrogen and progesterone

Question 22

which steroid hormone do the testes secrete?

Answer 22

testosterone

Question 23

what are the examples of the derivatives of tyrosine hormones?

Answer 23

Thyroxine and triiodothyronine

Catecholamines: Epinephrine and norepinephrine

Question 24

what are the steps in the synthesis of peptide and protein hormones?

Answer 24

preprohormone –> prohormone –> active hormone + scraps protein

Question 25

where is preprohormone synthesised?

Answer 25

in the endoplasmic reticulum

Question 26

what happens to the prohormone?

Answer 26

it is packed into secretory vesicles by the golgi complex

Question 27

what happens to the active hormone?

Answer 27

it is stored in secretory vesicles until released

Question 28

are peptide and protein hormones hydrophobic or hydrophilic?

Answer 28

hydrophilic

Question 29

do peptide and protein hormones need plasma protein binding for transport?

Answer 29

no, plasma protein binding is not essential for transportation of peptide and protein hormones.

Question 30

where are the receptors for peptide and protein hormones on their target cells?

Answer 30

on the surface, they cannot diffuse into the target cells.

Question 31

how do peptide and protein hormones function?

Answer 31

they function by either activating send messenger system, or changing ion channel permeability

Question 32

do peptide and protein hormones have a long or short duration of action?

Answer 32

short duration of action

Question 33

what is the precursor for steroid hormones?

Answer 33

cholesterol

Question 34

what are the steps in the synthesis of steroid hormones?

Answer 34

cholesterol --> pregnenolone --> to the different steroid hormones

Question 35

what determines what type of steroid hormone will be synthesised?

Answer 35

Pregnenolone is then converted to different steroid hormones in different steroidogenic organ depending on the set of enzymes that the organ contain.

Question 36

are steroid hormones hydrophobic or hydrophilic?

Answer 36

hydrophobic

Question 37

how are steroid hormones transported in the blood?

Answer 37

bound to plasma proteins

Question 38

where are the receptors on the target cells of steroid hormones?

Answer 38

the receptors are in cytoplasm or nucleus, steroid hormones can diffuse into the target cells

Question 39

how do steroid hormones function?

Answer 39

by activating specific gene in the target cell to cause the formation of new protein

Question 40

do steroid hormones have a short or long duration of action?

Answer 40

long duration of action

Question 41

are steroid hormones stored before being secreted?

Answer 41

no they are released into the blood as soon as they are synthesised

Question 42

are thyroxine and triiodothyronine hydrophobic or hydrophilic?

Answer 42

highly hydrophobic

Question 43

what are the properties of thyroxine and triiodothyronine

Answer 43

properties are similar to steroids hormones except that special mechanism exist to store this hormone in the thyroid gland

Question 44

are epinephrine and norepinephrine hydrophobic and hydrophilic?

Answer 44

they are small hydrophilic molecules

Question 45

what are the properties of epinephrine and norepinephrine?

Answer 45

properties are similar to that of peptide hormones

Question 46

how is the secretion of hormones regulated?

Answer 46

feed back loops - most common is negative feedback

Question 47

what is the hypothalamus?

Answer 47

the part of the brain which lies below the thalamus is the main centre responsible for homeostasis

Question 48

what does the hypothalamus do?

Answer 48

the hypothalamus receives information about the state of the body from various inputs

Question 49

where does the hypothalamus receive information from?

Answer 49

nucleus of the solitary tract, reticular formation, retina, circumventricular organs, limbic and olfactory systems

Question 50

does the hypothalamus receive information intrinsically?

Answer 50

yes, the hypothalamus also has some intrinsic receptors, including thermoreceptors and osmoreceptors to monitor temperature and ionic balance, respectively.

Question 51

how does the hypothalamus make the required adjustments?

Answer 51

neural signals to the autonomic system endocrine signals to/through the pituitary

Question 52

what is the pituitary gland (hypophysis)?

Answer 52

A small gland, 1 cm in diameter and about 0.5 g in weight that lies in sella turcia, a bony cavity

Question 53

why is the pituitary gland known as the master gland?

Answer 53

it controls most endocrine functions

Question 54

what type of hormones are released from the pituitary gland?

Answer 54

most hormones released by the pituitary gland are tropic hormones

Question 55

what are the 2 distinct portions of the pituitary gland?

Answer 55

``` anterior pituitary (adenohypophysis) posterior pituitary (neurohypophysis) ```

Question 56

where does the anterior pituitary (adenohypophysis) originate from?

Answer 56

Rathke’s pouch, a pharyngeal epithelium.

Question 57

where does the posterior pituitary (neurohypophysis) originate from?

Answer 57

it is actually an extension of the hypothalamus

Question 58

how is secretion from the pituitary controlled?

Answer 58

it is controlled by the hypothalamus.

Question 59

what does the posterior pituitary consist of?

Answer 59

the axons of 2 groups of hypothalamic secretary neurones

Question 60

what does the posterior pituitary secrete?

Answer 60

antidiuretic hormone (ADH) and oxytocin

Question 61

what produces ADH?

Answer 61

Neurons with cell bodies in supraoptic nuclei

Question 62

what produces oxytocin?

Answer 62

Neurons with cell bodies in paraventricular nuclei

Question 63

what hormones does the anterior pituitary secrete?

Answer 63

``` growth hormone (GH) adrenocorticotropin (ACTH) thyroid stimulating hormone/thyrotropine (TSH) Prolactin (PRL) follicle-stimulating hormone (FSH) luteinising hormone (LH) ```

Question 64

which cell type secretes GH?

Answer 64

somatotropes

Question 65

what cell type secretes ACTH?

Answer 65

corticotropes

Question 66

what cell type secretes TSH?

Answer 66

thyrotropes

Question 67

what cell type secretes LH and FSH?

Answer 67

Gonadotropes

Question 68

what cell type secretes PLR?

Answer 68

lactotropes

Question 69

what do the neurones within the hypothalamus secrete?

Answer 69

hormones that control secretion of hormones from the anterior pituitary

Question 70

what are the hypothalamic hormones referred to as?

Answer 70

releasing hormones and inhibiting hormones

Question 71

how are the hypothalamic hormones transported?

Answer 71

carried directly to the anterior pituitary gland via hypothalamic-hypophyseal portal veins.

Question 72

how do the hypothalamic hormones function?

Answer 72

Specific hypothalamic hormones bind to receptors on specific anterior pituitary cells, modulating the release of the hormone they produce.

Question 73

what makes up an endocrine axis?

Answer 73

Each endocrine axis consists of a hypothalamic factor(s), its pituitary target cell type and the ultimate target gland(s).

Question 74

what are the examples of the hypothalamus pituitary axes?

Answer 74

``` Hypothalamus-Pituitary Growth Hormone Axis Hypothalamus-Pituitary Adrenal Axis Hypothalamus-Pituitary Thyroid Axis Hypothalamus-Pituitary Gonadal Axis Hypothalamus-Pituitary Prolactin Axis ```