Week 5 endocrine system

Question 1

What is the endocrine system?

Answer 1

• synthesis of chemical messengers- hormones
• disseminated via bloodstream to specific target organs or act locally
• coordinate and integrate bodily funcitons

Question 2

What are endocrine organs generally composed of?

Answer 2

Islands of secretory epithelial cells with supporting tissue rich in blood and lymphatic capillaires

Question 3

Where is the pituitary gland located?

Answer 3

Extension below hypothalamus

Question 4

Name some of the target organs of pituitary glands

Answer 4

Breast, uterus - oxytocin
Kidneys - ADH
Ovaries/testes - FSH, LH

Question 6

What is the origin of the Posterior (neurohyoiohysis)

Answer 6

• enuroectoderm
• downgroeth of nervous tissue form hypothalamus
• maintains link with hypothalamus by pituitary stalk (infanfibulum)
• stains a lot lighter - myelinated axons

Question 7

What is the origin of the Anterior
(Adenohypophysis)

Answer 7

• oral ecoderm
• upgrowth form roof of primitive oropharynx
• rathke pouch
  Loses attachment with oral cavity

Question 8

Cleft separates by posterior and anterior

Answer 8

Pestigal
- left over form pouch
- forms part of pars intermedia

Question 9

What controls the pituitary gland?

Answer 9

Hypothalamus

Question 10

Hormones secreted by pituitary fall into 2 groups?

Answer 10

1. Those acting on non-endocrine tissues
2. Those modifying secretpry activity of other endocrine tissues

Question 11

Give examples of type 1

Answer 11

Growth hormone
ADH
prolactin
Oxytocin
MSH

Question 12

Give an example of type 2

Answer 12

TSH
ACTH
FSH
LH

Question 13

What are the thyroid, adrenal, gonads known as?

Answer 13

Pituitary-dependent endocrine glands

Question 14

Released continuously or in burst?

Answer 14

Usually bursts or circadium rhythms
Vary during menstrual cycle

Question 15

What is the posterior pituitary site of storage and relase of?

Answer 15

2 hormones
- adh (vasopressin) - synthesised in supraoptic nucleus
- oxytocin - synthesised in paraventriclar nucleus

Both pass down axons of hypothalamo-hypophyseal tract, within the pituitary stalk
- stored in distended axon terminal
- nerve impulses form hypothalamus control release

Question 16

What are herring bodies?

Answer 16

• posterior pituitary composed of non-myelinated axons
• cel bodies lie in supraoptic and paraventircular nuclei of hypothalamus
• secretory granules present all along axons
• most numerous in terminal distension where they meet capillarie s

Question 17

What are the three divisions of the anterior pituitary?

Answer 17

• pars distalis
• pars intermedia
• pars tubularis

Question 18

What is the fucntion of the anterior pituitary?

Answer 18

• hormone producitona nd secretion
• secretion regulated by hypothalamic releasing hormone

Question 19

What is thr pituitary derived from?

Answer 19

Ectoderm

Question 20

What are the main two cell tyoes of the anterior pituitary?

Answer 20

• darkly staining chromophils (basophils and acidophils)
• pale staining chromophobes

Question 21

What are the two types of chromophil cells?

Answer 21

Acidophil and basophil

Question 22

Mammotrophs

Answer 22

Increase during pregnanc

Question 23

Somatotrophs

Answer 23

Abt 50%
Growth hormone

Question 24

Descirbe the histology of the pars intermedia

Answer 24

• derived from remnants of rathke pouch
• composed of basophilic cells
• located between AP and PP
• systic structures containing colloid
• porduce poropiomelanocortin and MSh in foetal life

Question 25

What is the thyroid gland controled by?

Answer 25

Hypothalamus

Question 26

What hormones are released by thyroid?

Answer 26

TRH - stimulates thyroid cells to release TSH - negative feedback loop

Question 27

What is the histology of the thyroid gland

Answer 27

- basic unit is the follicles - speroidla sturcutre lined by cuboidal epithelium - vary in size filled with colloid - gland divided into lonules by septae

Question 28

What are the two major hormones produced by thyroid?

Answer 28

1. Tri-iodothyronine (T3) 2. Thyroxine (T4)

Question 29

What do the hormones produced by the thyroid do?

Answer 29

- Regulate how wuickly the body burns energy, makes proeitns, contorls how sensitive the body is to other homones - also porduces calcitonin

Question 30

Thyroid gland inacitve

Question 31

Thyroid gland acitve

Answer 31

Epithelial cells less suppressed

Question 32

Thyroid C cells

Answer 32

Calcitonin produced by parafollicluar Ccells - small clumps between follicles - calcitonin physiological antagonist of parathyoid hormone - lowers blood calcium levels

Question 33

parathyroid gland

Answer 33

Small 2-5 mm glands, closely related to thyroid (posterior surface) two pairs in most ppl

Question 34

histology of parathyroid gland

Answer 34

- parathyroid gland - thyroid gland - fibrous septum

Question 35

What are functions of the parathyroid?

Answer 35

Bone, kidney, intestine - calcium into blood stream

Question 36

descirbe the cell types of parathyroid cells

Answer 36

Two cell types - principle or chief cells - oxyphil cells

Question 37

describe principal or chief cells

Answer 37

- small dark nuclei, pale cytoplasm - most numerous - secrete PTH

Question 38

Describe ozyphil cells

Answer 38

- abundant pink cytoplasm - not knwon to have secretory role

Question 39

Adrenal gland

Question 40

Adrenal gland anatomy

Answer 40

On top of kidneys

Question 41

what are the two components of the adrenal gland

Answer 41

- adrenal cortex and medulla

Question 42

The adrenbal cortex seretes which hormones?

Answer 42

Steroid hormones

Question 43

Give examples of steroid hormones produced by adrenal cortex

Answer 43

- mineralocorticoids -> fluic and electrolyte balance - glucoocorticoids -> carbs and lipid balance - sex hormones

Question 44

name the three zones in the adrenal cortex

Answer 44

- zona glomerulosa - zona fasciculata - zona - reticularis

Question 45

What does the zona glomerulosa do

Answer 45

- cell clusters separate by fibrous septae - secrete mineralcorticoids - mainly aldosterone - acts on renal tubules to increase sodium and water retention

Question 46

What does the zona fasciculata do?

Answer 46

- columns of cells with abundant pale cytoplasm - one cell thick separated by capillaries - secrete glucoocorticoids, mainly cortisol

Question 47

What does the zona reticularis do?

Answer 47

- irregular groups of cells - separated by wide calibre capiries - source of adrenal androgens, DHEA, DHEAS and glucocorticoids

Question 48

Descirbe the histology of the adrenal medulla

Answer 48

- cluster of cells with granular, basophilic cytoplasm - very vascular - secrete adrenaline and noradrenaline - tun brown in chomiun salt fixative = chormaffin cells - cells secreting neuroadrenaline (Na) more strongly postive

Question 49

Descirbe the cells contianed in the endocrine pancreas

Answer 49

- islets of langerhands -> most numerous in tail -> groups and strands of cells around capillary network - 3 tyoes of cells: Alpha - glucagon Beta - insulin Delta somatostatin

Question 50

what is the funciton of the pineal gland?

Answer 50

Synthesis of melatonin - induces rthyhmical changes in endocrine activity

Question 51

Pinealocytes

Answer 51

Secrete melatonin into capillaries via long axons modified neurons

Question 52

Neuroglial cells

Answer 52

Support pinealocytes are modified astrocytes

Question 53

Basophilic pineal sand

Answer 53

Dalts of calcium magnesium and silicon - feature of aging gland

Question 54

Descirbe the histology of pineal glands

Answer 54

- small dark nuclei belond to the astrocytes found in pineal gland - pinealocytes have alrger, lighter and round nculei surrounded by brad rin of light cytmoplasmm , most nuclei present are nuckei pinealocytes - endothelial cell nuclei found in association wihth vesels and capillaries traverisn the tissue

Question 55

What do pinealocytes and astrocytes have in common?

Answer 55

Lonf processes which give the tissue between the nuclei its stringy appearance

Question 56

Describe the diffuse neuroendocrine system

Answer 56

- scattered neuroendocirne cells - GI systme - respiratory system

Question 57

Descirbe the GI system

Answer 57

Secretions include gastin, secretin, somatostatin VIP (vascoactive intestinal peptide)

Question 58

Descirbe the respiratory system

Answer 58

- secretions include serotonin, calcitonin, bombesin - act in endocrine or paracrine fashion