Anatomy and Physiology Flashcards
Negative feedback inhibiting hormone secretion from endocrine target to anterior pituitary/hypothalamus
Long-loop feedback
Negative feedback inhibiting hormone secretion from anterior pituitary to hypothalamus
Short-loop feedback
1st degree disorders are due to…
A defect in secretory cells
2nd degree disorders are due to…
Too much/ too little tropic hormone secreted from the pituitary gland
3rd degree disorders are due to…
Hypothalamic defects
Endocrine regions of the pancreas are called…
Islets of Langerhans
Rough normal blood glucose concentration
5 mmoles
Hypoglycaemia is blood glucose of…
<3mM
glucagon is produced by…
alpha cells in the islets of langerhans
Insulin secretion is stimulated by…
Amino acids and glucose in the blood
Somatostatin is secreted by…
Delta cells in the islets of langerhans
Function of somatostatin
- inhibits GI activity, slowing nutrient absorption
2. supresses release of insulin and glucagon
Net effect of the glucose counter-regulatory control system
Elevates blood glucose
Hormones making up the glucose counter-regulatory control system
Glucagon
Epinephrine
Cortisol
Growth hormone
Hyperexcitation of neurons (possibly leading to tetany) is caused by…
Hypocalcaemia
Reduced neuron excitability depressing neuromuscular activity (triggering cardiac arrhythmias in extreme cases) is caused by…
Hypercalcaemia
Increasing plasma pH has what effect on [ca2+] plasma?
Alkalosis –> hypocalcaemia
Actions of 21-hydroxylase
Enzyme needed for synthesis of aldosterone and cortisol
Mineralocorticoids (e.g. aldosterone) are produced in the…
Zona glomerulosa in the adrenal cortex
Glucocorticoids (e.g. cortisol) are produced in the…
Zona fasciculata in the adrenal cortex
Sex steroids are produced in which part of the adrenal gland?
Zona reticularis of the adrenal cortex
Catecholamines (e.g. epinephrine, dopamine) are produced in the…
Adrenal medulla
C (clear) cells of the thyroid secrete…
Calcitonin (Ca2+ regulating hormone)
The pituitary gland is situated in a hollow of the sphenoid bone called the…
Sella turcica
Which parts= of the pituitary gland is dark and which is light staining on H&E stain?
Dark = anterior pituitary Light = posterior pituitary
3 Types of anterior pituitary cells and how they stain
Acidophils - pink
Basophils - light purple
Chromophobic - pale
Arterial blood supply to the anterior pituitary
Superior hypophysial artery
Arterial blood supply to the posterior pituitary
Inferior hypophysial artery
The hypothalamus is connected to the posterior pituitary through the…
Infundibulum
Vertebral level of the thyroid
C5 - T1
The thyroid is located between which cartilages?
Cricoid cartilage and 6th tracheal ring
The isthmus lies opposite which tracheal rings?
2nd - 4th
Which nerve runs between the trachea and oesophagus?
Recurrent laryngeal nerve
Which nerve runs beside the superior thyroid artery
Superior laryngeal nerve
Acidophils secrete which anterior pituitary hormones?
GH and prolactin
Basolphils secrete which anterior pituitary hormones?
ACTH,
TSH,
FSH,
LH
Embryological origin of the adrenal cortex
Mesoderm
Embryological origin of the adrenal medulla
Neuroectoderm
Thyroglobulin is secreted in…
The follicular cell
it is then exocytosed into the colloid where it is iodinated
Specific action of TSH
catalyses endocytosis of iodinated thyroglobulin into the follicular cell
How are thyroid hormones transported in the blood
Bound to thyroxine-binding globulin
has a higher affinity for T4
Where is the thyroid hormone receptor located
In the target cell
higher affinity for T3 so most T4 is converted by deiodinase before/after entering the cell
Action of thyroid peroxidase
oxidizes iodide ions to form iodine atoms for addition onto tyrosine residues on thyroglobulin in the colloid
IGF-1 is secreted by…
+ action
Secreted by the liver stimulated by GH
inhibits release of GH and GHRH
Synthesis of calcitriol
Vitamin D converted to 25(OH)D3 in the liver
25(OH)D3 converted to Calcitriol by the kidney
stimulated by prolactin and PTH
General action of calcitriol
increases plasma calcium
General action of PTH
increases plasma calcium
The thyroid produces …….. in response to high plasma calcium
calcitonin
increases renal calcium excretion
The kidney converts 25(OH)D3 to……
Calcitriol
Hormones travel from the hypothalamus to the anterior pituitary in the…
hypophyseal portal system
ACTH release is stimulated by…
CRH
The posterior pituitary produces
Oxytocin
ADH
Basis of large vessel disease in diabetes mellitus
LDL is glycated
Glycated LDL is not removed from plasma by liver cells
causes hyperlipidaemia + atherosclerosis
Basis of small vessel disease in diabetes mellitus
glycosylation of basal lamina proteins thickens the basal lamina –> narrowed arteriole + ischaemia
Effects of insulin
increased glucose uptake by cells Glycogen synthesis Triacylglycerol synthesis increased amino acid uptake protein synthesis stimulates Na/KATPase --> increased potassium uptake
Specific action of insulin on fat and muscle cells
binds to tyrosine kinase receptors –> recruits GLUT4 transporters
action of insulin on liver cells
(only effective in the fed state)
insulin activates hexokinase –> lowers intracellular glucose –> glucose enters cell via GLUT 2