Endocrine System Flashcards
Two types of glands in endocrine system
Exocrine
Endocrine
Exocrine glands
Non-hormonal secretions transported through ducts to membrane surfaces of cells
Endocrine glands
Duct-less and secrete hormones into surrounding tissue fluid
Which type of gland is more vascular
Endocrine
Which type of gland targets specific organs
Endocrine
Pure endocrine organ
Only purpose is to secrete hormones
Hypothalamus
Produces molecules that control hormones
- Link between nervous and endocrine systems
- Located in temporal lobe
Amino acid based hormones
Protein based hormones that exert signalling effects once bound to receptor on cell surface
Steroids
Derived from cholesterol
Are AA or steroids more lipid soluble?
Steroids
Ae most hormones AA or steroids?
AA
Activation of target cell receptors depends on 3 factors
Blood level of hormone
Number of receptors on cell
Affinity between hormone and receptor
What is an example of a positive feedback system
Estrogen stimulates oxytocin release during childbirth
3 types of regulatory stimuli
Humoral
Neural
Hormonal
Humoral
Changing blood levels of molecules
Neural
Nerves stimulate hormone release
Hormonal
Release in response to hormones from other endocrine organs
Parathyroid Hormone
Responds to low levels of calcium in the blood (humoral response)
Location of the pituitary gland
Hypophyseal fossa in the sphenoid bone
What structure connects the pituitary to the hypothalamus
Infundibulum
How many hormones does the pituitary secrete
9
What is the posterior lobe of the pituitary made of
Neural tissue
What is the anterior lobe of the pituitary made of
Glandular tissue
3 structures that compose the Neuropophysis
Hypothalamus
Posterior pituitary
Infundibulum
What is the anterior boundary of the pituitary
Optic chiasma
What is the mammillary body involved in
Memory processing
Order of blood vessels supplying the anterior pituitary
Internal carotid artery
Superior hypophyseal artery
Anterior lobe
Dural sinuses and hypophyseal vein
8 Products of the pituitary
Oxytocin ADH ACTH TSH FSH LH GH PRL
Order of hypophyseal portal system
Hypothalamus sends releasing/inhibiting factors Hormones go to primary capillaries Hypophyseal portal veins Secondary capillaries Secretory cells
What blood vessel supplies the posterior pitutitary
Inferior hypophyseal artery
Where does the inferior hypophyseal artery drain
Capillary plexus of the infundibular process
Which pituitary lobe is part of the brain?
Posterior
Hypophyseal tract
Axons from the supraoptic and paraventricular nuclei maintain a connection between the posterior pituitary and the hypothalamus
Supraoptic Nucleus
Nucleus in hypothalamus that produces ADH (vasopressin) which enhances water absorption
Paraventricular nucleus
Nucleus in the hypothalamus that project to pituitary and release oxytocin and ADH
Location of PVN
In the hypothalamus, adjacent to the third ventricle
What 2 hormones are released during childbirth
Oxytocin
Progesterone
ADH
Peptide that inhibits urine formation to prevent water imbalance
Function of the anterior pituitary
Manufacture and release hormones
Origin of anterior pituitary
Rathke’s Pouch
Origin of posterior pituitary
Diencephalon
Connection of anterior pituitary to hypothalamus
Only vascular through hypophyseal portal system
Where does the anterior pituitary secrete products
Anterior hypophyseal vein
Pituitary adenoma
Benign tumour of epithelial cell origin
Hyperplasia
Excess growth
6 amino acid based hormones released by the pituitary
ACTH MSH GH TSH Gonadotropins Prolactin
Tropic hormone
Other endocrine glands are the target
Giantism
Growth hormone disorder of childhood
Acromelagy
Growth hormone disorder of adulthood
ACTH
Stimulates adrenal cortex to release corticosteroids to help body fight stressors
What is ACTH release stimulated by
Corticotropin releasing hormone from corticotrope cells
Cushing’s disease
Excess glucosteroids (cortisol) due to increased ACTH - Causes redistribution of fat-- buffalo hump, moon face
Melanocyte-stimulating hormone
Stimulates melanin production for skin pigmentation and appetite control
GHRH
Produced in the hypothalamus and stimulates release of GH from somatotropes
Somatostatin
Inhibits release of GH and blocks GI and pancreatic cecretions
Targets for GH
Epiphyseal plates in bones and skeletal muscle
Thyroid Stimulating Hormone
Produced by thyrotropes and stimulated by TRH
- Stimulates development and secretions of the thyroid
Gonadotropins
Secreted by gonadotropes and stimulated by gonadotropin-releasing hormone
Lutenizing hormone
Type of gonadotropin that onsets ovulation causing release of progesterone
Follicle stimulating hormone
Type of gonadotropin that stimulates release of estrogen and gamete production
Prolactin
Produced by lactotropes
- Stimulates milk production
Order of abundance of anterior pituitary histology
Somatotropes Corticotropes Lactotropes Thyrotropes Gonadotropes
What is the largest pure endocrine gland
Thyroid
Where is the thyroid located
Anterior neck
- C5-T1 vertebrae
Isthmus
Connects the right and left lobes of thyroid
Where is the Isthmus located
Tracheal rings 2-3
2 vessels supplying the thyroid
Superior thyroid artery
Inferior thyroid artery
Superior thyroid artery
Branch of the external carotid artery
Inferior thyroid artery
Branch of the thyrocervical trunk of the subclavian artery
3 hormones produced by thyroid
T3
T4
Calcitonin
What are T3 and T4 mostly compose dof
Iodine
Effects of T3 and T4
Increase metabolic rate and body heat production
Maintain blood pressure
Involved in growth and development
Calcitonin
Lowers blood Ca by inhibiting osteoclast activity
-Stimulates Ca uptake in bones
Hyperthyroidism (Grave’s Disease)
Autoimmune disease caused by overproduction of thyroid hormone
Effects of hyperthyroidism
Increased metabolism and sweating
Rapid irregular heart beat, weight loss
Exopthalmos
Protrusion of eyeballs caused by hyperthyroidism
Treatments for hyperthyroidism
Thyroidectomy
Ingestion of Iodine 131
Hypothyroidism
Causes decreased metabolic rate, chills lethargy and edema
How is T3 produced
Thyroid stimulating hormone from the pituitary stimulates thyroid to produce T3 with dietary iodine
Goiter
Huge thyroid enlargement from prolonged stimulation of TSH in the absence of iodine
Thyroid nodules
Tumours of the thyroid gland
- most common endocrine malignancy
Parathyroid Glands
4 nodes on posterior thyroid
Tetany
Muscular disorder resulting from low Ca
What is a cause for tetany
Accidental removal of the parathyroid glands
How does PTH act on the kidneys and small intestine
Promoting formation of calcitrol (active vitamin D) which aids in calcium absorption
Adrenal gland
Pyramid shape on the superior pole of the kidney
What encloses the adrenal gland
Fibrous connective tissue capsule that covers the kidney
3 vessels supplying the adrenal gland
Superior suprarenal artery
Middle Suprarenal artery
Inferior suprarenal artery
Superior suprarenal artery
Branch of the inferior phrenic artery
Middle suprarenal artery
Branch of the abdominal aorta
Inferior suprarenal aorta
Renal Artery
What composes 85% of the adrenal gland
Adrenal cortex
What 2 steroids does the adrenal cortex produce
Mineralcorticoids
Glucocorticoids
What are the two lobes of the adrenal gland
Cortex: glandular tissue
Medulla: Neural tissue
Mineralcorticoids
(Aldosterone) increase blood levels of salt and walter
Glucocorticoids
(cortisol) Stress resistance, immune function and inflammatory response
Adrenal medulla
Neural tissue derived from neural crest
What are the 2 products released by the adrenal medulla
Epinephrine and norepinephrine (catecholamines)
Epinephrine
(80%) Stimulates heart and metabolic activity
Norepinephrine
Stimulates vasoconstriction and blood pressure
Effects of long term stress response
Retention of sodium and water by kidneys
Increased blood volume and pressure
Increased blood sugar
Suppression of immune system
Pancreas
Accessory digestive organ with exocrine and endocrine processes
Exocrine cells in the pancreas
Acinar cells: produce enzyme secretions that duct into the small intestine
3 endocrine cells in the pancreas
Alpha: glucagon
Beta: Insulin
Delta: somatostatin
Which pancreatic cell responds to hypoglycemic conditions
Glucagon
Islet of langerhans
Pancreas cells alpha, beta and delta
4 parts of the pancreas structure
Head
Neck
Body
Tail
Which parts of the pancreas is pouched in the small intestine
Head and neck
Which parts of the pancreas are associated with the spleen
Tail
4 vessels that supply the pancreas
Celiac trunk
Common hepatic artery
Splenic artery
Superior mesenteric artery
Glucagon
Releases glucose to the body
Glycogenesis
Breakdown of glycogen to glucose
Glucogenesis
Glucose is formed from lactic acid, fats and amino acids
What does insulin stimulate
Glucose storage in cells- glucose to glycogen
When do alpha cells release glucagon
When blood sugar is low (humoral)
When does gestational diabetes take effect
between 24-28 weeks gestation
What regulates the gonads
Gonadotropins
What two hormones effect the female gonads
Estrogen
Progesterone
Where is the pineal gland located
Roof of the 3rd ventricle, part of the dicephalon
Pinealocytes
Cells that secrete melatonin
What hormone does cardiac muscle produce
Atrial naturetic peptide
What does ANP counteract and act with
Counteracts Aldosterone
Acts with ADH
What 3 hormones does the placenta secrete
Estrogen
Progesterone
Human Chorionic Gonadotrophin (hCG)
What hormone does the mucosa of GI organs produce
Gastrin: Stimulates release of HCl for digestion
What hormone does adipose tissue produce
Leptin: Acts in CNS to produce feeling of satiety
What opposes leptin
Orexin (hypothalamus)