Exocrine Endocrine Stuff 💘

Question 1

Exocrine parts of pancreas

Answer 1

90% exocrine
Exocrine produces bicarbonate amylase protease lipase .
Produces buffering solution and enzymes to aid digestion

Question 2

Endocrine parts of pancreas

Answer 2

10% endocrine (lighter regions)
Islets of langerhans
These produce insulin glucagon somatostatin pancreatic polypeptide and ghrelin
Controls hunger sensation and glucose homeostasis

Question 3

Acinus

Answer 3

Cluster of cells that resemble a many lobed berry

Question 4

Intercalated ducts

Answer 4

Portion of the exocrine gland that drains from acting’s into larger ducts and eventually the intralobular duct
Helps takes enzymes
Secretes bicarbonate

Question 5

Bicarbonate secretion from duct cells

Answer 5

Apical And bicarbonate secretion by interaction of the CL & K ion channels and apical cl-/HCO3- exchange
the basal membrane contains sodium potassium pump establishes and out in sodium concentration gradient that serves as a driving force for intracellular accumulation hco3- via na/h exchange

Question 6

Bicarbonate secretion part 2 (secretin)

Answer 6

Secretin activates potassium and calcium channels via generation intracellular camp.
Activation of basolateral potassium channels hyper-polarizes the cells favoring apical CL efflux through camp activated CL channels.
Favor recycling of chloride that’s taking in to cell by sale by chloride bicarbonate exchange

Question 7

Cholecystokinin

Answer 7

Responsible for digestion of fat and protein

Produced by i cells and acts on acinus to release digestive enzymes

Question 8

Secretin

Answer 8

Hormone that regulate water homeostasis and secretions in the stomach and duodenum is produced by S cells and acts on the intercalated ductal cells to release bicarbonate.
Both hormone release is controlled by Vagus nerve

Question 9

Percentage of each cell type

Answer 9

Alpha 20-25
Beta 70-75
Delta <5
Epsilon <1
Pp cell >1

Question 10

Delta cells produce

Answer 10

Somatostatin

Question 11

Epsilon produces

Answer 11

Ghrelin

Question 12

Pp cells produce

Answer 12

Polypeptides

Question 13

Insulin synthesis

Answer 13

Preproinsulin targeted by 24aa signal peptide and taken to RER
Single polypeptide cleaved forming proinsulin
Prounsulin folds 3 disulphide bonds form then moves to trans golgi network
Matures ti active form due to endopeptidases releasing c peptide fragment
Packaged into granules and wait for release

Question 14

Two forms of insulin

Answer 14

Hexameric- inactive storage form. Three folds held together by zinc forming histidine bonds
Monomeric- active form, half life of 6 mins, composed of alpha and beta chains linked via disulphide bridges

Question 15

Insulin secretion

Answer 15

Glucose sensing and uptake by GLUT2
Causes rise in atp causing depolarisation and k+ flows in
Causes Calcium influx and storages granules release insulin via exocytosis

Question 16

IRS1

Answer 16

Triggers movement of GLUT 4 glucose receptor to cell surface for glucose uptake

Question 17

Glucagon synthesis

Answer 17

29aa polypeptide generated by proprotein convertsse 2 cleaving Pro glucagon in alpha cells

Question 18

Cystic fibrosis

Answer 18

Caused by frameshift mutation in the cystic fibrosis conductance regulator gene.
Affects lungs pancreas liver and intestine
Abnormal transport of chloride and sodium across the epithelium leading thick viscous secretions that block exocrine movement of digestive enzymes

Question 19

Anterior Pituitary gland nerves and contents

Answer 19

axons from hypothalamus release neurohormones into primary plexus into hypothalamo hypophyseal portal system and it’s endocrine cells produce hormones
Contains chromophobes and chromophils (acidophils and basophils)

Question 20

Posterior pituitary gland nerves and contents

Answer 20

Axons from hypothalamus release neurohormones directly into arterial system
Contains neural tissue and non myelinated axons
Pituicytes support glial type cells

Question 21

Thyroid gland

Answer 21

Composed of many follicles
Follicular cells are a single layer of epithelium which surround each folllicle
Centre of follicle is colloid which stores hormones
Para follicular cells are less numerous lighter in colour larger and secrete calcitonin

Question 22

Parathyroid gland

Answer 22

Two superior and two inferior
Contained within connective tissue capsule
Have chief cells and secretory granules which contain pth
Also have oxyphil cells

Question 23

Thyroid hormone release

Answer 23

Thyrotropin relaxing hormone produced by neurons in the hypothalamus stimulates release of tsh and prolactin in anterior pituitary
Tsh stimulates thyroid release 83% t4 7% t3
Also produced calcitonin

Question 24

Thyroid action

Answer 24

Stimulates metabolic rate- increases number and size of mitochondria
Also has positive inotropic and chronotropic effects on heart and important in growth and development in skeletal and nervous system

Question 25

Thyroid formation

Answer 25

Iodide atoms actively transported across follicular cells and are trapped in colloid and oxidised to iodine by thyroid peroxidase I2 then attaches to tyrosine molecule iodine+ tyrosine =MIT 2 iodine and tyrosine=DIT MIT+DIT=t3 DIT+DIT=t4 T3 mainly made in liver and kidney

Question 26

Congenital hypothyroidism

Answer 26

Absence or ectopic thyroid All neonates screened this (Guthrie blood spot) Treated with life long thyroxine

Question 27

Acquired hypothyroidism

Answer 27

Via iodine deficiency Decreased t3 and t4 which increase tsh and trh due to lack of negative feedback Symptoms include decreased metabolic rate

Question 28

Autoimmune thyroiditis (hashimotos disease)

Answer 28

Associated with thyroid peroxidase and thyroglobulin antibodies Causes chronic thyroid damage and drip of blood hormone over years More common in females

Question 29

Secondary hypothyroidism

Answer 29

Due to something other than gland eg pituitary Tumour (can’t produce tsh)

Question 30

Hyperthyroidism

Answer 30

Main causes are autoimmune thyroid diseases and toxic nodular goitre Overproduction of t3&t4 surpassing tsh levels

Question 31

Thyroid eye disease

Answer 31

Protrusion of eyes Lid lag (white if eyes above and below iris come visible) Opthalrhoplegia eyes are not straight Can cause double vision and increased damage risk

Question 32

Hyperthyroidism treatment

Answer 32

Inhibit iodide oxidation by thyroid peroxidase Ptv Beta blockers to alleviate symptoms Radioactive iodine if other drugs unsuccessful Or total thyroidectomy (surgery) (lifelong thyroxine)

Question 33

Primary hyper parathyroidism

Answer 33

Usually due to a single benign parathyroid adenoma causing overproduction of pth Symptoms of hypercalcaemia Treated surgically unless it’s modest then ca levels monitored instead

Question 34

HPA axis

Answer 34

Negative feedback system Hypothalamus produces CRH which causes anterior pituitary to release acth Stimulates adrenal cortex to release cortisol High levels of cortisol then inhibits ant pituitary and hypothalamus

Question 35

Adrenal insufficiency

Answer 35

Adrenal glands fail to produce enough cortisol Primary is problem with adrenal gland Secondary is problem with pituitary gland Tertiary problem in hypothalamus

Question 36

Primary adrenal insufficiency | Secondary tertiary

Answer 36

Aka Addison’s disease High levels of acth Acts on melanocytes yo produce more melanin causing hyper pigmentation In secondary high CRH in tertiary CRH ACTH and cortisol low

Question 37

Testing for adrenal conditions

Answer 37

If u suspect insufficiency u stimulate to see response If u suspect over functioning u suppress the gland Synacthen stimulation test for adrenal insufficiency use ACTH and see if ride in cortisol after 30 mins For secondary you do insulin stress test

Question 38

Hypercortisolemia

Answer 38

Aka cushings disease causes protein depletion and poor wound healing and osteoporosis Due to high acth and low crh Tested with dexamethasone test-absence of supressuon yo dexamethasone =cushings disease

Question 39

Prolactin action

Answer 39

Baby sucks on breast stimulates hypothalamus to stimulate pituitary yo produce prolactin producing milk More it sucks more milk produced

Question 40

Ghrh

Answer 40

Ghrh>gh>igf1 (liver)> growth and development and stress