Endocrine System - Zainab Adnan

Front 1

Name the major endocrine glands

Back 1

Hypothalamus

Pituitary

Thyroid

Parathyroid

Pancreas

Adrenal glands/ suprarenal

Front 2

What is a gland?

Back 2

Glands = collection of cells that makes and releases a substance for biological use

Front 3

What are EXOCRINE glands? Give 2 examples

Back 3

Secrete directly onto target via duct

Salivary glands, sweat glands

Front 4

What is an ENDOCRINE gland?

Back 4

No duct

Secrete into interstitial fluid and transported to target indirectly via bloodstream

Front 5

What gland is it likely to be if it is directly next to target organ?

Back 5

Exocrine

Front 6

If a hormone released by a gland effects multiple different parts of the body, what type of gland is it likely to have been released by?

Back 6

Endocrine

Front 7

What two other parts of the body composition are unexpectedly endocrine?

Back 7

Bone

Fat

Front 8

What is the hypothalamus made of?

Back 8

Collection of nuclei (gray matter) at the base of the brain

Front 9

Describe the anatomical position of the hypothalamus

Back 9

Forms part of the wall and the 3rd ventricle

Front 10

What is the function of the hypothalamus?

Back 10

Link neurosensory system to endocrine system

Coordinates ANS (unconscious) and ENDOCRINE

Front 11

Hypothalamus is also a site for many...

Back 11

Converging and diverging neural pathways. Hypothalamus has connections to lots of different parts of the brain and body

Front 12

Where does the hypothalamus receive info from?

Back 12

Neurons

Blood

CSF (cerebral spinal fluid)

Front 13

What is the ventricle in the brain full of?

Back 13

CSF

Front 14

What are the nuclei in the hypothalamus made of?

Back 14

Small neurones arranged into functional groups. Each nuclei is responsible for different functions.

(learn these seperate positions)

Front 15

What are some of the roles in the body that the hypothalamus is responsible for?

Back 15

Thermoregulation

Osmoregulation

Satiety

ANS control

Front 16

Why is anatomical descriptions used for the different nuclei?

Back 16

Useful for imaging assessment

Front 17

What is the pituitary gland made up of?

Back 17

Anterior part

Posterior part

Hint 17

Front 18

How is the pituitary gland linked the the hypothalamus?

Back 18

The posterior part is an Extention of the hypothalamus

Front 19

Where physically does the pituitary gland sit?

Back 19

In the pituitary fossa of the skull - completely surrounded by bone

Front 20

How is the hypothalamus linked to the pituitary gland physiologically?

Back 20

Hypothalamus Coordinates the release of hormones from the pituitary gland. Does it differently for the anterior and posterior pituitary (since posterior is linked by neurones and anterior isn't)

Front 21

Key hormones of anterior pituitary gland - target organ - what is stimulates in target organ

Back 21

Prolactin - mammary glands - milk production

Growth - MSK - growth, cell reproduction / regeneration

Thyrotropin - thyroid gland - T3, T4 production

Adrenocorticotropic - Adrenal Cortex- releases cortisol

Gonadotropins (FSH/ LH) - ovaries/ testes

Front 22

How does the pituitary gland release hormones?

Back 22

In response to hormones releases by the Hypothalamus

Front 23

What are the two types of hormones the hypothalamus releases?

Back 23

Releasing hormones (RH)

Inhibitory hormones (IH)

Front 24

Prolactin IH is also known as?

Back 24

Dopamine

Front 25

What is the function of the posterior pituitary gland?

Back 25

Stores and secretes the hormones produced by the Hypothalamus, doesn't synthesise any of its own hormones

Front 26

What are the 2 hormones secreted by the posterior pituitary gland?

Back 26

Vasopressin (Anti diuretic hormone)

Oxytocin

Front 27

What connects the posterior pituitary gland to the hypothalamus?

Back 27

Infundibulum

Front 28

Hormones produced in the hypothalamus reach the pituitary by two way? In anterior and posterior?

Back 28

Anterior via portal blood vessels

Posterior via neuroendocrine cells

Front 29

Which nuclei influence parasympathetic activity? (rest and digest)

Back 29

Pre-optic

Anterior hypothalamic area

Front 30

Which nuclei influence sympathetic activity? (fight or flight)

Back 30

Posterior

Lateral

Front 31

Which nucleus influences pituitary activity? (hormonal homeostasis)

Back 31

Anterior nuclei

Front 32

What is the scientific name for Adams apple?

Back 32

Laryngeal prominence

Front 33

What connects the two lobes of the thyroid? Over what tracheal rings are these?

Back 33

Isthmus

2-4

Hint 33

Front 34

What is the top and bottoms of the thyroid gland called?

Back 34

Apex

base

Front 35

What 3 main hormones does thyroid release

Back 35

Thyroxine (T4)

Tri-idothronine (T3)

Calcitonin (lowers blood calcium)

(T tells you it's made in thyroid and number is number of iodine)

Front 36

Is T3 or T4 more active? Which does body produce more and what happens when that molecule enters cells?

Back 36

T3

Thus T4 is produced more, which is broken down into T3 when it gets to cells

Front 37

What do T3 and T4 do?

Back 37

Increase basal metabolic rate

Increase body temp (calorigenic effect)

Stimulates protein synthesis (growth and development)

Inhances catecholamines

Front 38

Identify following on an ultrasound

Back 38

As seen in pic

Front 39

Thyroid development in an embryo

Back 39

At 4 weeks;

Invagination of endoderm in pharynx floor - grows into "thyroid diverticulum". Then develops a thyroid gland at the end of it by week 5

Front 40

How can thyroglossal cysts form?

Back 40

Thyroglossal duct may remain open and a gathering of mucus within it leads to infection

Front 41

How many parathyroid glands are there?

Back 41

4, in each corner at the posterior of the thyroid glands

Hint 41

Front 42

What is the Parathyroid gland secretion controlled by?

Back 42

Calcium levels in blood

Front 43

What does the secretion of Parathyroid hormones cause?

Back 43

Increases calcium levels by releasing calcium from bones and increasing the amount of calcium absorbed at the small intestines. When Ca2+ levels are too high, less PTH is produced

Front 44

Is Pancreas an endocrine or exocrine gland?

Back 44

Both

More than 95% is exocrine

Front 45

What organ is it intricately related to?

Back 45

Duodoneum

Front 46

What type of structural gland is the Pancreas?

Back 46

Lobulated

Front 47

What does the Pancreas consist of

Back 47

Head

Neck

Body

Tail

Front 48

What is the endocrine part of the Pancreas called?

Back 48

Clusters of cells called islets of langerhans

Front 49

Key hormones produced by Pancreas

Back 49

Glucagon: increases bg

Insulin

Somatostatin : decreases release of pancreatic hormones and muscle contraction

Vasoactive intestinal peptide (VIP)

Pancreatic polypeptide (PP)

Front 50

Where do you find suprarenal glands? Aka Adrenal glands

Back 50

Upper poles of kidneys

Hint 50

Front 51

What are the shapes or right and left suprarenal glands?

Back 51

Right is a pyramid

Left is a crescent

Hint 51

Front 52

How many different layers of tissue do the Adrenal glands have? What are their names?

Back 52

3

Capsule

Cortex

Medulla

Front 53

How many zones does the Cortex have and what is produced in each zone?

Back 53

Zona glomerulus - aldosterone

Zona fasciculata - cortisol

Zona reticularis - sex hormones

Front 54

What does the medulla produce?

Back 54

Catecholamines (adrenaline/ noradrenaline)

Front 55

Is kidneys an endocrine organ?

Back 55

Yes

Front 56

Kidneys produce a hormone vital for Red blood cell production called?

Back 56

Erythropoetin (EPO)

Front 57

Describe the RAAS

Back 57

Pathway designed to increase blood pressure

Front 58

What does the thyroid gland wrap around?

Back 58

Cricoid cartilage

Front 59

Thyroid position anatomy

Back 59

In visceral compartment of the neck

Between C5-T1

Below thyroid cartilage of larynx

Anterior to the upper trachea and cricoid cartilage

Hint 59

Front 60

Arterial blood supply to the thyroid gland. 2 x pathways

Back 60

Common carotid

External carotid

Superior thyroid artery (feed tops of thyroid gland with blood)

Subclavian artery

Thyrocervical trunk

Inferior thyroid artery (feed bottoms of thyroid gland with blood)

Hint 60

Front 61

What 3 veins drain the thyroid gland of its blood?

Back 61

Superior thyroid vein

Middle thyroid vein

Inferior thyroid vein

Hint 61

Front 62

Where does the blood from the 3 thyroid veins go?

Back 62

Superior and middle thyroid veins drain into the internal jagular vein

The Inferior drain into brachiocephalic veins

Front 63

Describe the embryology of the thyroid gland. Where does it originally develop? What is the embryological remnant?

Back 63

Base of the tongue

Foremen caecum

Front 64

Where does the thyroid go, through what?

Back 64

Descents from base of tongue to base of neck at the level of cricoid cartilage via thyroglossal duct

Front 65

What happens at the end of week 5? What has happened by the 6th weeks?

Back 65

Thyroglossal duct degenerates

Then

Throid has reached itrs destination

Front 66

What are the functional units of the thyroid?

Back 66

Follicular cells

Front 67

What are follicular hormones cells responsible for?

Back 67

Production and secretion of T3 and T4. They're also TSH (thyroid stimulating hormone) dependent

Front 68

What cells are found interlocking between follicular cells and what is their function?

Back 68

C-cells / parafollicular cells

These produce calcitonin (calcium homeostasis)

Front 69

What are the target cells for T3 and T4?

Back 69

Cells in all tissue types

Front 70

Describe thyroid hormone action

Back 70

Binds directly to nuclear receptors THR receptors and results in transcription factors and alters gene expression

Front 71

Learn biosynthesis, storage and secretion of thyroid hormones

Back 71

Please

Front 72

Which form of thyroid hormones is active and inactive?

Back 72

Active; T3

Inactive; T4

Front 73

What is the cavity inside follicular cells called?

Back 73

Lumen

Front 74

What is colloid?

Back 74

Colloid is the sticky fluid filling the thyroid follicular lumen. It contains Thyroglobulin (TGB) w/ attached to newly synthesised T3 and T4 for storge (iodine ions present)

Front 75

How are thyroid hormones synthesised?

Back 75

1) I- is actively up taken from blood into follicular cells via Na+/I- Symporters (both into the cell) . Then it diffuses into lumen by passive diffusion where it is oxidised (2I- ➡️ I2)

2) Thyroglobulin is synthesised by the follicular cell also and released into the lumen via exocytosis

3) Tyrosine molecules on the TGB undergo iodination to form MIT and DIT

4) MIT + DIT =T3

DIT + DIT = T4

5) colloid enters follicular cells via pinocytosis and merges with lysosomes. Digestive enzymes breakdown TGB leaving T3 and T4

Front 76

What is MIT AND DIT

Back 76

Monoiodotyrosine

Diioditryosine

(tyrosine is the functional units of the TGB that the iodide binds to)

Front 77

Where is T4 broken down into T3?

Back 77

Liver and kidneys

Front 78

Where does TSH come into all this?

Back 78

Binds to TSH receptors on the follicular cell and causes endocytosis of droplets of colloid into the follicular cell where digestive enzymes in the lysosomes break down TGB and release T3 and T4 into the blood stream

Front 79

Describe the hypothalamic - pituitary - thyroid axis (negative feedback loop). How are levels of thyroid hormones in the blood increased?

Back 79

1) hypothalamus detects low circulating T3/T4/thyroid hormone

2) responds by releasing thyrotropin- releasing hormone (TRH) which stimulates the anterior pituitary gland to produce TSH

3) TSH stimulates thyroid gland to produce thyroid hormones and levels increase in blood

Front 80

How are levels of thyroid hormones decreased?

Back 80

TSH is an inhibitor for the hypothalamus producing TRH

Thyroid hormones are inhibitors for the anterior pituitary and hypothalamus

Front 81

What is hypothyroidism?

Back 81

TSH LEVELS ARE HIGH

T3 / T4 LEVELS ARE LOW

Front 82

What is hyperthyroidism?

Back 82

TSH LEVELS ARE LOW

T3 & T4 LEVELS ARE HIGH

Front 83

Effects of hyperthyroidism

Back 83

Increased basal metabolic rate

Wight loss, good appetite

Diarrohea

Warm sweaty skin, heat intolerance

Tachycardia

Front 84

Effects of hypothyroidism

Back 84

Decreased basal metabolic rate

Weight gain, anorexia

Dry skin

Brady

Constipation

Front 85

What does calcitonin do?

Back 85

Lowers release of calcium ions and phosphates by inhibiting bone resorption (opposite action of Parathyroid hormone)

Front 86

Name 3 sex steroids

Back 86

Testosterone

Estrogen

Progesterone

Front 87

What are these three sex hormones formed from?

Back 87

Cholesterol

Front 88

How is progesterone produced from cholesterol?

Back 88

Cholesterol to pregnenolone

Pregnenolone to progesterone

Front 89

How is testosterone produced from cholesterol?

Back 89

Cholesterol to pregnenolone

Pregnenolone to testosterone

Front 90

How is estrogen formed from cholesterol?

Back 90

Cholesterol to pregnenolone

Pregnenolone to testosterone

Testosterone to estrogen

Front 91

What enzyme converts testosterone to estrogen?

Back 91

Aromatase

Front 92

Where is testosterone produced? In men and in women (small amounts)

Back 92

Men: leydig cells

Females: theca interna in ovaries

Front 93

When is the concentration of testosterone highest in the blood? What is this pattern called?

Back 93

In the morning

Circadian rhythm

Front 94

What does testosterone do?

Back 94

Muscle growth

Spermatogenesis

Secondary male sexual characteristic

Front 95

What are the levels of testosterone and estrogen controlled by?

Back 95

LH & FSH

Front 96

What are the 3 types of estrogen? Which one is the main type?

Back 96

Estrone

Estradiol - main

Esteriol

Front 97

How is estrogen produced? In men too?

Back 97

Females :By granulosa cells of follicle

Through conversion of testosterone via aromatization

Placenta

Males: sertoli cells of testi

Front 98

What does estrogen do?

Back 98

Bone mass

GnRH regulation

Ovulation

Cardiovascular Physiology

Neuronal growth

Front 99

What is progesterone?

Back 99

A pregnancy hormone which initiates and maintains conditions for pregnancy

Front 100

What does progesterone do?

Back 100

Enhances endometrium secretion

Inhibits uterine contractions

Maintains pregnancy

Increases body temperature

Inhibits GnRH release

Front 101

Where is progesterone produced? Name 3

Back 101

Corpus luteal cells

Adrenal glands

Placenta

Front 102

What is hypogonadism?

Back 102

Due to lack of estrogen and testosterone (hormones which help develop gonads) there is an underdevelopment of gonads

Front 103

Hypogonadism can be primary or secondary. When is it primary vs secondary?

Back 103

Defect at the level of gonad

Defect at pituitary or hypothalamus level causing reduced FSH/ LH levels or reduced GnRH secretion

Front 104

Where are the Parathyroid glands located? What do the Parathyroid glands consist of?

Back 104

Posterior of thyroid gland

4 small oval shaped glands

Front 105

What is the function of Parathyroid glands?

Back 105

They secrete Parathyroid hormone in response to low calcium serum level

Front 106

What cells are the Parathyroid glands made up of?

Back 106

Cheif cells

Oxyphil cells

Front 107

What do the cheif cells secrete?

Back 107

Parathyroid hormones

Front 108

Which nerves supply the Parathyroid gland?

Back 108

Nerves derived from thyroid branches of the cervical ganglia

Front 109

Embryology of the Parathyroid gland? Superior and Inferior

Back 109

Superior Parathyroid glands originate from the 4th pharyngeal pouch

Inferior Parathyroid glands a derived from the 3rd pharyngeal pouch

Front 110

What G protein does PTH use?

Back 110

Adenyl cyclase pathway

Front 111

How does the Parathyroid gland determine calcium levels?

Back 111

Receptors

Front 112

How is Parathyroid hormone activated?

Back 112

Pre prohormone to

Pro hormone to

Active hormone

Front 113

What does PTH do? Where does it do this?

Back 113

Activates 1 alpha hydroxylase in kidneys which converts CALCIDIOL into CALCITRIOL

Front 114

What is the active form of vitamin D?

Back 114

CALCITRIOL

Front 115

What does Vitamin D do? In the intestines? Kidneys? Bone?

Back 115

Maintains calcium serum levels in general:

Increases Ca2+ absorption in GI tract

Increases bone resorption to release Ca2+ (vitamin D binds to the osteoblast which then release RANKL which causes Ca2+ reabsorption)

Increases reabsorption of Ca2+ in kidneys

Front 116

What are the arteries that supply blood to the Parathyroid glands?

Back 116

Inferior thyroid arteries

Front 117

What are the veins that drain the Parathyroid gland?

Back 117

Parathyroid vein into thyroid venous plexus

Front 118

Where can you find VDR (Vitamin D receptor) and PTHR (Parathyroid hormone receptor)? Baso where does Vitamin D act?

Back 118

Intestines

Kidneys

Bone

Front 119

What else causes calcium serum levels to increase?

Back 119

Parathyroid horomes

Binds to Parathyroid hormone receptors in kidneys and bone and increase calcium serum levels

Front 120

Describe the synthesis of Vitamin D

Back 120

7-Dehydrocholesterol

Cholecalciferol

Calcidiol

CALCITRIOL

Front 121

How is 7-Dehydrocholesterol converted into Cholecalciferol? Where does this take place?

Back 121

UVB

Skin

Front 122

How is Cholecalciferol converted into calcidiol? Where does this take place?

Back 122

Enzyme 25 hydroxylase

Liver

Front 123

How is calcidiol converted into CALCITRIOL? Where does this happen?

Back 123

1 a-Hydroxylase enzyme

Kidneys

Front 124

What activates 1 a-Hydroxylase?

Back 124

PTH activates it

Front 125

What is calcium used for?

Back 125

Neuronal excitability

Muscle contraction Inc cardiac

Blood clotting

Cell devision / adhesion

Front 126

What is phosphate stored as? What is it used for?

Back 126

Stored as hydroxyapatite in bones - skeletal integrity

ATP production

Front 127

What are the 3 hormones involved in calcium level management?

Back 127

Vitamin D

Parathyroid Hormone

Calcitonin

Front 128

What happens when ca2+ levels decrease?

Back 128

Increase in PTH

Effects bone and kidneys to

Front 129

How does PTH and CALCITRIOL effect bone?

Back 129

Inhibits osteoblast

Stimulate osteoclasts

Bone is broken down releasing Ca2+ into the bloodstream

Front 130

How does PTH and Calcitriol effect the kidneys?

Back 130

PTH = an increase in PTH increases absorption of Ca2+ from kidneys and decreases phosphate reabsorption. Calcium serum levels increase but phosphate serum levels drop

Calcitriol = an increase in Calcitriol increases absorption of Ca2+ and phosphate ion reabsorption from the kidneys

Front 131

What does Calcitriol do to the GI track?

Back 131

Increases number of calcium and phosphate channels in the GIT. So increases absorption of both ions

Front 132

What happens in response to increased Ca2+ levels?

Back 132

Parafollicular cells of the thyroid glands are stimulated by high conc of ca2+ and produce calcitonin.

Front 133

What is the effect of calcitonin on bone?

Back 133

Stimulates osteoblast

Inhibits osteoclasts

Calcium is removed from blood and used to build bone

Front 134

Overall effect of PTH on calcium and phosphate levels?

Back 134

Loss of phosphate from the kidneys is greater than phosphate absorbed from gut and bone - overall increase calcium and decreased phosphate

Front 135

Osteoblasts vs osteoclasts

Back 135

Osteoblasts - B - build bone

Osteoclasts - C - crash bone

Front 136

What does this mean?

Back 136

Hint 136

Hydroxyapitate releases both Ca and PO4

Front 137

What causes hypoparathyroidism? What things can cause this?

Back 137

Low PTH & low calcium serum levels

Surgical removal or auto immune disorders

Front 138

What causes pseudohypoparathyroidism? What things cause it?

Back 138

High PTH

Target organ resistance to PTH - developmental disorder

Front 139

What are some clinical features of hypoparathyroidism? My Mum Can Never Tell Truth

Back 139

Muscle weakness

Muscle cramps

Chvosteks sign

Nerve function

Trousseau sign

Tetany

Front 140

What is hyperparathyroidism?

Back 140

Increased secretion of PTH

Front 141

What are the two types of hyperparathyroidism?

Back 141

Primary - increased PTH due to a disorder to the gland (benign tumour)

Secondary - compensatory oversecretion. Nothing is wrong with the gland but conditions like kidney failure and vit D deficiency decrease calcium levels which increases PTH

Front 142

Symptoms of hyperparathyroidism

Back 142

Often asymptomatic

But can be ;

Constipated

Psychosis

EVG changed - short QT interval

Front 143

What can be some complications of hyperparathyroidism?

Back 143

Osteoporosis

Kidney stones

Peptic ulcers

Pancreatitis

Front 144

How is glucose transported into cells?

Back 144

Via 2 types of transporters:

- sodium dependent glucose transporters (SDGTs)

- facilitative glucose transporters (GLUT's)

Front 145

How do SGDTs work? Where are the present?

Back 145

These are sodium/ glucose co-transporters (secondary active transport). They uptake glucose from the intestines with sodium into epithelial cells

Front 146

What are GLUT's?

Back 146

Passive

Glucose transporters via Facilitated diffusion

Front 147

How many GLUT's are there?

Back 147

5

Front 148

Where is Glut 1 found?

Back 148

Brain

Erythrocytes

Placenta

Fetal tissue

Front 149

What is special about Glut 1?

Back 149

Has a high affinity for glucose therefore uptake of glucose is constant

Front 150

Where is Glut 2 found?

Back 150

Tissues

(liver, kidneys, intestine, pancreatic beta cells)

Front 151

What does insulin do to Glut 2?

Back 151

Increases up takes of glucose by Glut 2 but the liver itself does not need the insulin in order to uptake glucose

Front 152

Where is Glut 3 found? Why is Glut 3 special?

Back 152

Brain

Allows preferential uptake of glucose in a hypoglycemic state

Front 153

Where is Glut 4 found?

Back 153

Muscle

Adipose tissue

(insulin stimulates a cascade reaction to store glucose)

Front 154

Where is Glut 5 found?

Back 154

Jejunum (part of small intestine)

Front 155

Describe the mechanism of insulin action in Glut 4

Back 155

1) insulin binds to tyrosine kinase receptors

2) triggers protein kinase cascade

3) Glut 4 transporters travel to cell surface by exocytosis

4) glucose enters the cell

Front 156

What is glucose converted into in Adipose tissues?

Back 156

Fatty acids

Front 157

What is glucose converted into in the liver and skeletal muscle?

Back 157

Glycogen

Front 158

Anatomy of the Pancreas

Back 158

-Upper left quadrant

-Posterior to stomach

-Anterior to kidneys

-Retroperitoneal except for tail which is intra peritoneal

Front 159

How many parts does the Pancreas have and what are they called?

Back 159

4

Head

Neck

Body

Tail

Front 160

What are the functions of Pancreas?

Back 160

Digestion (exocrine)

Hormone production (endocrine)

Front 161

What proportion of the Pancreas is endocrine function vs exocrine function?

Back 161

10% endocrine

90% exocrine

Front 162

What hormones do alpha cells release? What is the target organ?

Back 162

Glucagon

Liver

Front 163

What hormones do beta cells release?

Back 163

Insulin

Front 164

What hormones do delta cells secrete? What is the action of this hormone?

Back 164

Somatostatin which Inhibits the secretion of insulin and glucagon (and GHRH)

Front 165

What do PPcells release? (diagram calls these F cells) what does this inhibit?

Back 165

Pancreatic polypeptide which Inhibits the secretion of Somatostatin

Front 166

Exocrine functions of the Pancreas?

Back 166

Secrete enzymes which neutralise and digest food in the intestines

Front 167

What can the exocrine portions of the Pancreas be divided into?

Back 167

Lobules

Front 168

What are lobules made up of?

Back 168

Acinar cells

Ductal cells

Front 169

What do aciner cells do?

Back 169

Release digestive enzymes

Front 170

What do Ductal cells do?

Back 170

Secrete fluid and bicarbonate

Front 171

What 3 things are alpha cells stimulated by?

Back 171

Low blood glucose in fasting state

Sympathetic nervous system

Rise in blood amino acids

Front 172

What is the function of glucagon?

Back 172

Increase blood glucose levels

Stimulate glycogenolysis

Stimulates gluconeogenesis

Inhibits glycogenesis

Front 173

What stimulates beta cells?

Back 173

High glucose in fed state

Parasympathetic NS

Gastric inhibitory polypeptide (GIP) and glucogon-like-peptide-1

Front 174

What is the function of insulin? What does insulin suppress in the liver?

Back 174

Lowers blood glucose levels

Increase uptake & storage of glucose, fatty acids, aa in liver & muscle tissue

In liver suppresses gluconeogenesis

Front 175

How do beta cells work?

Back 175

1) glucose enters the cells via GLUT-2

2) glucose is converted into Glucose-6-phosphate via glucokinase

3)G6P stimulates glycolysis to produce ATP

4)ATP sensitive potassium channels close

5)potassium build up in the cell opens voltage gated calcium channels

6)increased ca2+ induces secretion of insulin

Hint 175

Front 176

What are the Incretins that also Stimulate insulin secretion after a carb rich meal?

Back 176

GIP

GLP - 1

Front 177

What are some causes of hypoglycemia?

Back 177

Excessive alcohol consumption

Hormonal abnormalities

Overdose of insulin

Front 178

Role of Adrenal glands in glucose regulation. What is released during fasting?

Back 178

Adrenaline is released during fasting

Cortisol is secreted in prolonged fasting (form of stress)

Front 179

What does Adrenaline do in a hypoglycemic state?

Back 179

Promotes glycogenolysis in liver and skeletal muscles

Front 180

What does cortisol do in a hypoglycemic state?

Back 180

Supports gluconeogenesis in the liver by mobilising aa from skeletal muscles

Front 181

What is type 1 diabetes?

Back 181

Insulin deficiency

Front 182

What is type 1 diabetes caused by?

Back 182

Autoimmune destruction of pancreatic beta cells

At least 18 genes are involved + complex environmental interactions

Front 183

What age does type 1 diabetes develop?

Back 183

Any age but typically childhood

Front 184

What are the effects of having type 1 diabetes?

Back 184

Uncontrolled gluconeogenesis

Use of alternative fuels

Development of hyperglycaemia

Ketoacidosis

Eventual coma and death if untreated

Front 185

What is Ketoacidosis?

Back 185

Uncontrolled catabolism of lipids

Front 186

What is type 2 diabetes?

Back 186

Insulin resistance and insulin deficiency

Target tissues become unresponsive to insulin

Front 187

What happens when people develop. Type 2 diabetes?

Back 187

Target tissues are unresponsive to insulin. Pancreatic beta cells produce even more insulin to compensate so bg levels remain normal but eventually the cells function progressively declines and there's an insulin deficiency thus hyperglycemia

Front 188

What age does type 2 typically develop?

Back 188

Over 40

Front 189

What is a major factor risk factor for type 2 diabetes?

Back 189

Obesity

This is linked to the insulin resistance and beta cell dysfunction

Front 190

Describe the mechanism of insulin resistance

Back 190

Increased stress on cells since they're constantly metabolising incoming glucose

Cells becomes overwhelmed with glucose and send signals to down regulates insulin receptors on its surface to stop glucose entering

Front 191

What is the neuroendocrine system?

Back 191

Nervous and endocrine systems work together

Front 192

What is the hypothalamus made up of?

Back 192

Groups of neurons called nuclei

Front 193

What is the name of the blood vessel network in the hypothalamus?

Back 193

Hypothalamo-hypophysial- portal system

Front 194

Where is the anterior pituitary derived from?

Back 194

Ectoderm of Rathke's pouch

Front 195

Where is the posterior pituitary derived from embryologically?

Back 195

Downward extension of neural ectoderm from the floor of the diencephalon

Front 196

What is the name of the bulb next to the pituitary gland but below hypothalamus?

Back 196

Optic chasm

Hint 196

Front 197

What is the name of the neck of the anterior pituitary?

Back 197

Pars tuberalis

Front 198

What is the name of the membrane in between the anterior and posterior pituitary?

Back 198

Pars intermedia

Front 199

What is the name of the body of the anterior pituitary?

Back 199

Pars distalis

Front 200

What is the neck of the posterior pituitary called?

Back 200

Infundibular stalk

Front 201

What is the body of the posterior pituitary called?

Back 201

Pars nervosa

Front 202

How does hormone action from the anterior pituitary work?

Back 202

1) hypothalamic neurons secrete releasing hormones

2) hypothalamo-hypophysial portal system

3) releasing hormones Stimulate pituitary hormone secretion

4) exit via vein to target tissue or endocrine gland

Hint 202

Front 203

How does posterior pituitary hormone action work?

Back 203

1) hypothalamic neuron

2) hypothalamo-hypophysial tract

3) posterior pituitary

4) vein and into the blood stream

Hint 203

Front 204

What starts the GHRH-GH-IGF1 Axis?

Back 204

Stress and low blood glucose stimulates increased release of GHRH and decreases production of GHIH (inhibiting hormone)

GH produced then Inhibits the production of GHRH

Front 205

What mediated the effects of GH?

Back 205

IGF - 1

Front 206

Where is IGF-1 produced?

Back 206

Liver in response to GH stimulation

Front 207

Main function of GH in children and adults?

Back 207

Children: linear growth

Adults: protein synthesis

Carbohydrate metabolism

Lipolysis

Calcium homeostasis

Front 208

Describe the CRH - ACTH - Adrenal axis

Back 208

Stress/ hypoglycemia

Release of CRH

Via hypothalamo-hypophysial portal system to anterior pituitary

ACTH released

Adrenal cortex releases cortisol

Front 209

What does cortisol inhibit?

Back 209

ACTH and CRH production

Front 210

What does cortisol do?

Back 210

Increases glucose production

Increases protein breakdown

Increases fat breakdown

Front 211

TRH-TSH- THYROID AXIS

Back 211

TRH from hypothalamus

Causes TSH release from anterior

Stimulates thyroid to make T3 & T4

T3 & T4 inhibit TSH & TRH release

Front 212

What action do T4 & T3 bring?

Back 212

-increased heart rate and Cardiac output

-increased bone turnover and resorption

-increased gut mobility

-breaks down fats

-increases catecholamines sensitivity in the sympathetic nervous system

Front 213

Prolactin axis?

Back 213

Anterior releases prolactin

Hypothalamus releases dopamine to inhibit prolactin production

Front 214

Which nuclei is ADH produced in?

Back 214

Supraoptic nucleus

Front 215

Which nuclei is oxytocin produced in?

Back 215

Paraventricular nucleus

Front 216

What oxytocin do?

Back 216

-milk ejection (suckling is stimulus)

-stimulates myoepithelial contractions (in uterus during childbirth and in mammary glands during lactaions)

Front 217

What does ADH do?

Back 217

-conserves body water

-water deprivation increases osmolality of plasma which activates hypothalamic ossmoreceptors to stimulate ADH release

Front 218

What are some other functions of the hypothalamus?

Back 218

Thirst control

Temperature

Autonomic nervous system

Appetite and hunger

Sleep and circadian rhythm

Front 219

Which hormone can penetrates the plasma membrane?

Back 219

Estrogen

Front 220

G-protein coupled receptors are at the site of interaction for what? What are G proteins?

Back 220

Catecholamines (G-protein are proteins which bind signal molecules outside the cell, transduct the signal into the cell and cause a cellular response)

Front 221

Which hormone Inhibits release of growth hormone from the anterior pituitary?

Back 221

Somatostatin

Front 222

Leptin regulates food intake through interactions with what?

Back 222

The hypothalamus

Front 223

Where is calcium reabsorbed in the kidneys?

Back 223

60% PCT

15% thick ascending

10-15% DCT (this is where PTH and Calcitriol would act)

Front 224

What is acromegaly?

Back 224

When pituitary gland produces too much growth hormone during adulthood. This leads to swollen hands and feet, larger features, abnormal periods and erectile dysfunction. Tiredness/ sleep apnoe

Front 225

What is Addison's disease?

Back 225

Under production of cortisol and aldosterone due to autoimmune destruction of Adrenal gland. Can present at any age. Symptoms are: weight loss, dizzy spells, hyperpigmentation, frequent urination

Front 226

Which gland produces melatonin?

Back 226

Pineal gland

Important in sleep cycle

Front 227

What is leptin?

Back 227

A hormone from fat that controls food intake

Front 228

What is conn's syndrome/ primary hyleraldosteronism?

Back 228

Too much aldosterone production

Causes hypertension and metabolic alkalosis

Front 229

What is cushing's syndrome?

Back 229

Increase in ACTH release leading to the production of excess cortisol

Front 230

What is pgeochromocytoma (PCC)?

Back 230

A tumour in the Adrenal medulla of the Adrenal glands. Causes the Adrenal glands to make too much noradrenaline and adrenaline

Front 231

What is white adipose tissue? What is the function?

Back 231

-A single large membrane enclosed lipid droplet and few mitochondria

-modest blood supply

-function is lipid storage and hence insulation

Front 232

What does white adipose tissue secrete?

Back 232

Leptin

Asprosin (during fasting to cause rapid release of glucose from the liver)

Front 233

What is brown adipose tissue?

Back 233

-Contains many small lipid droplets and lots of mitochondria (giving brown colour)

-rich in blood supply

Front 234

What is the function of brown adipose tissue?

Back 234

Thermogenesis (process of heat production in body)

Front 235

What hormones are responsible for appetite regulation?

Back 235

Leptin

Ghrelin

Insulin

Front 236

When is leptin secreted? What does leptin inhibit?

Back 236

Released from adipose tissues. More fat = more leptin released

Decreases appetite and suppresses hunger

Leptin Inhibits insulin production and secretion. In contrast, insulin stimulates leptin secretion from adipose tissues

Front 237

What does ghrelin do?

Back 237

Released by G cells in response to empty stomach (walls not Stretched)

Acts on GHS-R on Arcuate nuclei

Increases appetite, decreases thermogenesis and increases insulin production (baso opposite to white and brown adipose tissue action)

Front 238

What protein converts cholesterol into pregnenolone?

Back 238

Steroidogenic Acute Regulatory Protein (StAR)

Front 239

What are the cells of anterior pituitary and what are they responsible for?

Back 239

Somatotrophs - GH

Thyrotrophs - TSH

Ginadotrophs - FSH and LH

Lactotrophs - Prolactin

Corticotrophs - ACTH and MSH

Front 240

GH can act in two ways:

Back 240

Direct

Indirect

Front 241

How does GH act directly?

Back 241

GH binds to receptors on adipose tissues and target cells. Causes them to breakdown triglycerides and suppress their ability to take up lipids.

GH is released when theres hypoglycaemia, low fatty acids, high aa, in deep sleep, in the presence of the rest of the anterior pituitary hormones. GHRH acts in somatotrophs to produce GH

Front 242

What is the indirect action of GH?

Back 242

Mediated by insulin-like growth factor (IGF-1) a hormone that is released by the liver in response to GH

IGF-1 stimulates osteoblasts at the epiphyseal plate, increasing uptake of aa (for protein synthesis) and increasing blood glucose

Front 243

What Inhibits GH?

Back 243

GHIH/ SOMATOSTATIN is released in response to GHRH and Inhibits GHRH release

Front 244

What is gigantism?

Back 244

Caused by adenoma, a tumour of the pituitary gland. Excessive growth hormone in childhood