Endocrine and Exocrine

Question 1

What are glands and what types are there?

Answer 1

Epithelial cells that produce secretions. Endocrine and Exocrine

Question 2

What do endocrine glands do?

Answer 2

produce hormonal secretions into interstitial tissue then into capillaries. they have no ducts

Question 3

How can endocrine glands exist?

Answer 3

these can be either part of an epithelial surface such as the lining of the GIT (gastrointestinal tract) or separate organs such as the thyroid or pituitary gland.

Question 4

What do hormones produced do?

Answer 4

The hormones produced regulate bodily functions and maintain homeostasis.

Question 5

What are the patterns of hormone secretion and what are some hormone examples of them?

Answer 5

Chronic - thyroxine (tetraiodothyronine)
Acute - adrenaline, cortisol
Episodic - insulin

Question 6

What are the mechanisms that regulate hormone secretion

Answer 6

humoral (blood borne molecules such as high glucose in blood)

neural (neurons stimulate hormone production)

hormonal (hormone secretion stimulates another hormone to be secreted)

Question 6

What are the classes of hormones and where are they stored?

Answer 6

proteins and polypeptides secreted by the pancreas and parathyroid can stored in cell

steroids secreted by ovaries, placenta, adrenal cortex, synthesised by cholesterol are released immediately and cannot be stored

derivatives of amino acid tyrosine secreted by the adrenal medulla and the thyroid

Question 7

Where is the thyroid gland found?

Answer 7

The thyroid gland is located in the midline of the neck in front of the trachea.

Question 8

Describe how the thyroid gland secretes hormones

Answer 8

Inactive hormones are stored in colliod surrounded by secretory cells, which make up a ‘follicle’.

These follicles are lined by a single layer of cuboidal epithelium that is known as follicular epithelium.

When this epithelium is active, the shape can change to a columnar epithelium.The follicular cells contain thyroxine T4 and tri-iodothyronine T3 which are the active hormone.

Question 9

When the follicular epithelium of the thyroid gland is active, what is the shape change?

Answer 9

simple cuboidal to simple columnar

Question 10

What other secretory cells are present in the thyroid gland and what do they secret?

Answer 10

c cells (parafollicular) secrete calcitonin which helps keep calcium levels in our body normal

Question 11

How many parathyroid glands are there and where are they situated?

Answer 11

4 and in the corners of the thyroid glands

Question 12

What does the parathyroid gland do?

Answer 12

It secretes hormones called the parathyroid hormone (PTH) which has effect on the osteoclasts which are responsible for bone resorption (breakdown)

Question 13

What happens when calcium levels decrease?

Answer 13

When calcium and other minerals levels decrease, the parathyroid glands secrete the hormone and this activates the osteoclasts to break down bone. The minerals are then released into the body, bringing up the levels to within the normal range. Once normal level is reached, the hormone secretion stops.

Question 14

What happens in the case of hyperparathyroidism and how is it caused?

Answer 14

caused by a benign tumour or hyperplasia of the gland. this results in increases hormone secretion, increased bone resorption and increased calcium level. eventual wear and lesion of jaw

Question 15

What are the main hormones responsible for calcium metabolism?

Answer 15

calcitonin
PTH (parathyroid hormone)
vitamin D

Question 16

What are the cells in the parathyroid gland?

Answer 16

chief cells (synthesise PTH), oxyphil cells

Question 17

How do secretions of exocrine glands work?

Answer 17

secretions are released through ducts that open onto the epithelial surface

Question 18

How are exocrine glands classified?

Answer 18

by structure or method of secretion

Question 19

What are the exocrine, structure classifications?

Answer 19

Unicellular (goblet)
Multicellular -arranged in pockets or sheets

Question 20

What are the types of multicellular structure?

Answer 20

duct system may be branched (compound gland) or unbranched (simple gland)

secretory component may be tubular or acinar

both types of secretory components may be coiled or branched

Question 21

What are the exocrine methods of secretion and how do they function?

Answer 21

Merocrine gland produces substances stored in little bubbles (vesicles) in the cytoplasm. They are released into the duct and carried out to secrete. Mostly protein secretion

Apocrine produces substances that are carried with parts of the cells and leaves through the apical part –mammary glands

Holocrine produces substances that are carried with entire dying cells that secrete. Cells are replaced –sebum

Question 22

What are the different types of multicellular glands and where are they found?

Answer 22

simple tubular - stomach, colon (large intestine)
simple branched tubular - lower portion of stomach
simple coiled tubular -lower portion of stomach and small intestine, sweat glands
simple acinar - sebaceous glands of skin
compound tubular - mucous glands of duodenum
compound acinar - mammary glands
compound tubiloacinar - pancreas

Question 23

What are the types of secretions?

Answer 23

Serous –behind ears very protein rich (watery)

Mucous –contain glycoproteins, secrete mucins which hydrate to form mucus (thick)

Mixed glands –have both

Question 24

What are the major salivary glands?

Answer 24

Parotid. Submandibular. Sublingual

Question 25

What is specific about the pancreas?

Answer 25

it has both endocrine and exocrine glands

Question 26

What are islets of langerhans and what cells do they secrete?

Answer 26

they are endocrine cells that secrete insulin (beta cells) glucagon (alpha cells) somastatin and gastrin (nuclei of delta cells) f cells (pancreatic polypeptide)

Question 27

How does type one diabetes occur?

Answer 27

destruction of beta cells therefore no insulin secretion

Question 28

What are the oral effects of diabetes?

Answer 28

dry mouth, periodontitis

Question 29

What are the disorders of the endocrine systems (endocrinopathies)?

Answer 29

hypofunction (reduced hormone release) hyperfunction (increased hormone release) hormone resistance (diabetes mellitus)

Question 30

What type of secretion is produced by blue-coloured acini in alcian blue and H&E stains?

Answer 30

mucous

Question 31

What type of secretion is produced by pink-coloured acini in alcian blue and H&E stains?

Answer 31

serous, they have not taken up the blue stain

Question 32

What do the parotid glands secrete?

Answer 32

parotid glands consist almost exclusively of serous cells and produce a thin watery secretion rich in enzymes and antibodies.

Question 33

What type of secretion is produced by the magenta-stained cells in a PAS stain?

Answer 33

mucous

Question 34

What kind of secretion do the submandibular glands secrete?

Answer 34

both serous and mucous secretory cells and produce a secretion of intermediate consistency.

Question 35

What increases in the sublingual gland with age?

Answer 35

the proportion of adipose tissue (fat) in the gland generally increases with increasing age.

Question 36

What type of secretion stains poorly with H&E?

Answer 36

mucous

Question 37

Which salivary gland has similar histological features to the lacrimal gland

Answer 37

parotid gland

Question 38

What are both mucous and serous acini surrounded by?

Answer 38

serous and mucous acini are surrounded by contractile cells called myoepithelial cells

Question 39

Which halogen is essential for the endocrine function of the thyroid?

Answer 39

iodine

Question 40

Why is the thyroid gland unique compared to other endocrine glands?

Answer 40

stores large amounts of hormone in an inactive form within extracellular compartments in the centre of follicles;

Question 41

Which thyroid hormones are partially composed of iodine?

Answer 41

T3 (Triiodothyronine) and T4 (Tetraiodothyronine, also known as thyroxine) are iodine-containing hormones.

Question 42

Which cells are responsible for the conversion of thyroglobulin, stored in the follicle, into T3 and T4?

Answer 42

Thyroid epithelial (follicular) cells

Question 43

Which cells are responsible for the secretion of calcitonin?

Answer 43

C or parafollicular cells

Question 44

The parathyroid hormone is produced by which cells?

Answer 44

chief cells

Question 45

What best describes the function of the parathyroid hormone?

Answer 45

Stimulate osteoclast activity

Question 46

What are the two components of the adrenal gland?

Answer 46

adrenal cortex, adrenal medulla

Question 47

In the histological zone of the adrenal cortex, zona glomerulosa, describe the arrangement

Answer 47

lies beneath the capsule and contains secretory cells arranged in rounded clusters.

Question 48

In the histological zone of the adrenal cortex, zona fasciculata, describe the arrangement

Answer 48

the intermediate zona fasciculate consists of parallel cords of secretory cells disposed at right angles to the capsule.

Question 49

In the histological zone of the adrenal cortex, zona reticularis, describe the arrangement

Answer 49

the zona reticularis lies close to the medulla and consists of small closely packed cells arranged in irregular cords. often the borders of the zones are less regular and less easily recognised than for the other zones.

Question 50

Name the hormone produced within the zona glomerulosa?

Answer 50

aldosterone

Question 51

Name the hormone produced within the zona fasciculata?

Answer 51

cortisol

Question 52

Name the groups of hormones produced exclusively within the zona reticularis?

Answer 52

androgens

Question 53

Why is rich vascularisation of the medulla required?

Answer 53

get important hormones such as adrenaline and noradrenaline around the body fast

Question 54

Which type of cells do you find in the Islet of Langerhans?

Answer 54

alpha cells, beta cells, delta cells, pancreatic polypeptide (PP) cells

Question 55

What is the function of insulin?

Answer 55

Promotes glucose uptake by most cells, Inhibits gluconeogenesis in the liver

Question 56

What is the medical term for dry mouth?

Answer 56

xerostomia

Question 57

Why do serous and mucous glands stain differently?

Answer 57

Mucous cells produce mucus, which doesn't stain very darkly, so the mucous cells look almost clear on these images and on slides. Serous cells produce a watery secretion that contains a lot of proteins. Serous cells stain fairly dark.

Question 58

What does the liver secret?

Answer 58

bile

Question 59

What kind of secretion does the sublingual gland have?

Answer 59

mostly mucous

Question 60

What is the function of the thyroid hormone?

Answer 60

regulates the basal metabolic rate and has an important influence on growth and maturation, particularly of nerve tissue

Question 61

What does calcitonin do?

Answer 61

Calcitonin lowers blood calcium levels by inhibiting the rate of decalcification of bone by osteoclastic resorption and by stimulating osteoblastic activity

Question 62

Where is TSH secreted from?

Answer 62

pituitary gland

Question 63

What hormones are example of tyrosine derivatives?

Answer 63

adrenaline T3, T4

Question 64

What is the embryological origin of glands?

Answer 64

ectoderm