Endocrine

Question 1

Where is the hypothalamus located

Answer 1

In the anterior end of the diencephalon

Question 2

What are the direct links between the hypothalamus and the anterior pituitary gland

Answer 2

The vascular links of the hypothalamic – hypophyseal portal system

Question 3

How is secretion of the posterior pituitary controlled

Answer 3

By nerve signals that originate in the hypothalamus

Question 4

Name six hormones released from the hypothalamus

Answer 4

Corticotropin releasing hormone (CRH)

Growth hormone releasing hormone (GHRH)

Thyrotrophin releasing hormone (TRH)

Gonadotrophin releasing hormone (GnRH)

Growth hormone release inhibiting hormone/somatostatin

Dopamine

Question 5

What is another name for the anterior pituitary

What does it consist of

Answer 5

Adenohypophysis

Glandular epithelial tissue

Question 6

What hormones do we need to know that are secreted from the anterior pituitary

Answer 6

Growth hormone, 
prolactin, 
adrenocorticotrophic hormone, 
thyroid stimulating hormone
 follicle stimulating hormone
 luteinising hormone

Question 7

What secretes GH

Answer 7

Somatotrophs (about 50% of bulk of anterior pituitary)

Question 8

What secretes prolactin

Answer 8

Lactotrophs– 20% of anterior pituitary but this increases during pregnancy

Question 9

What secretes ACTH

How much of the anterior pituitary does this take up

Answer 9

Corticotrophs

20%

Question 10

What secretes TSH

Answer 10

Thyrotrophs (5% of anterior pituitary)

Question 11

What secretes FSH and LH

How much of the anterior pituitary does this take up

Answer 11

Gonadotrophs

5%

Question 12

What does pars distalis refer to

Answer 12

The major anterior part of the anterior pituitary

It is separated from the posterior pituitary by the Pars intermedia

Question 13

What is the pars tuberalis

Answer 13

An upward extension of the anterior pituitary which forms a partial or total collar of cells around the infundibular stem

The pars tuberalis and infundibular stem together make up the pituitary stalk

Question 14

What is the pars intermedia

Answer 14

A thin area of tissue lying against the posterior pituitary

It is rudimentary in humans compared to other mammals

It secretes MSH

Question 15

What is MSH

Answer 15

Melanocyte stimulating hormone

Question 16

What is the pars nervosa

Answer 16

The posterior pituitary or neurohypophysis

Question 17

How is the posterior pituitary connected to the hypothalamus

Answer 17

Via the pituitary stalk

Question 18

What are the staining properties of anterior pituitary hormones

Answer 18

Acidophilic: GH, PRL

Basophilic: ACTH, FSH, TSH, LH

Question 19

Are the neurons of the posterior pituitary myelinated

Answer 19

No

Question 20

How are the nerves divide in the posterior pituitary

Answer 20

Neurons in the supra optic nuclei are primarily ADH producing

Paraventricular nuclei produce mainly oxytocin

Question 21

What are the terminal axons from the hypothalamus to the posterior pituitary supported by

Answer 21

Glial cells known as pituitcytes which surround the unmyelinated axons

Question 22

Discuss The ultrastructure of cells in the anterior pituitary

Answer 22

They are typical of those of a peptide secreting cell

They are characterised by numerous secretory granules in the cytoplasm as well as prominent Golgi apparatus, ER and mitochondria

The Endocrine cells are surrounded by numerous sinusoid capillaries of the pituitary portal system that have penetrated endothelium and carry away secreted hormones

Question 23

Where is the thyroid located and what does it consist of?

Answer 23

Located in the anterior neck region in front of the upper trachea

It consists of two lateral lobes is connected by a breach of tissue called the isthmus

Question 24

Where is the pyramidal lobe of the thyroid

Answer 24

Extends up from the isthmus

Question 25

How many parathyroid glands are there

Answer 25

Usually 4 but this number can vary

Question 26

What is T4 and T3

Answer 26

T4= thyroxine T3= triiodothyronine They are iodine containing hormones synthesised by the follicular cells of the thyroid gland

Question 27

What are C cells

Answer 27

Parafollicular cells in the thyroid which release calcitonin

Question 28

What does calcitonin do

Answer 28

Plays a role in calcium regulation

Question 29

What do the parathyroid glands synthesise What does it do

Answer 29

Parathyroid hormone (PTH) Plays a role in calcium And phosphate regulation

Question 30

What is the functional unit of the thyroid

Answer 30

The thyroid follicle

Question 31

Describe the structure of a thyroid follicle

Answer 31

Spherical structure is composed of one layer of follicular cells which have a nucleus located at the base of the cell

Question 32

What do thyroid glands contain

Answer 32

Thousands of follicles filled with colloid

Question 33

What is the main component of colloid

Answer 33

Thyroglobulin

Question 34

How common are C cells in the thyroid

Answer 34

They are less common and sparsely distributed sometimes referred to as clear cells

Question 35

What do you C cells look like

Answer 35

Large, rounded, with a clear and light structure

Question 36

Where are c cells found

Answer 36

In humans: primarily located within the thyroid follicle between the basal area of the follicular cells and the basement membrane such that they have no contact with the colloid

Question 37

What do parathyroid glands consist largely of

Answer 37

Chief/principal cells and oxyphil/acidophilic cell

Question 38

What do chief cells and oxyphil cells do in the parathyroid

Answer 38

Chief cells are responsible for the synthesis and secretion of PTH Oxyphil cells do not secrete PTH their physiological role is not clear

Question 39

Oxyphil cells are often absent in which group of people

Answer 39

Young individuals: their number increases with age

Question 40

Describe the difference in morphology between active follicular cells and less active follicular cells

Answer 40

Active: high and columnar Less active: flattened

Question 41

How can the inner adrenal medulla be considered Name 3 things secreted here

Answer 41

As a sympathetic ganglion in which postganglionic neurons have lost axons and become secretory cells The catecholamines: adrenaline, noradrenaline and dopamine

Question 42

What does the zona glomerulosa secrete

Answer 42

Mineralocorticoids, mainly aldosterone

Question 43

What do the cells of the zona glomerulosa look like

Answer 43

They tend to aggregate into a regular round clusters surrounded by capillaries of wide diameter The cells have a strongly stained round nucleus and poorly stained cytoplasm

Question 44

What is the widest zone of the adrenal cortex and what do it cells look like? What does it secrete?

Answer 44

Zona fasciculata That consists of narrow cords of large cells, separated by a wide diameter, fenestrated capillaries Glucocorticoids, mainly cortisol

Question 45

How much of the adrenal cortex is the zona reticularis What does it consist of What does this zone secrete

Answer 45

5-10% Irregular network of branching cords, with numerous capillaries of wide diameter Androgenic steroids

Question 46

How is the adrenal medulla arranged

Answer 46

In clumps and cords of cells known as chromaffin cells surrounded by supporting tissue containing numerous wide diameter, fenestrated capillaries

Question 47

Describe the Venous channels of the adrenal medulla

Answer 47

They drain blood from the capillaries of the cortex past through the middle that towards the central medullary vein

Question 48

Describe the cells of the adrenal medulla

Answer 48

Large nucleus and a basophilic cytoplasm

Question 49

What is released from the adrenal medulla

Answer 49

Catecholamines are stored in membrane-bound granules which are released by exocytosis

Question 50

In humans and dogs which hormone is released most from the adrenal medulla What about the cats

Answer 50

Adrenaline Noradrenaline