Endocrine System Flashcards
define hormones
secretion from some glandular part of the body, which is poured directly into the blood and which acts on the target organs or cells of the same individual, bringing about coordination between distant parts of the body
general properties of hormones
- hormones are secreted from their source directly into the blood
- regulate the physiological processes by chemical means
- act on target organs or cells away from the source
- hormones produced in one species show similar influence in other species
- produced in small quantities, biologically very active
endocrine glands
- adrenal
- pancreas
- thyroid
- pituitary
location of adrenal glands
caps on the top of each kidney
parts of adrenal
- central medulla
- outer cortex
adrenal medulla
secretes adrenaline
stimulated by nerve endings of autonomic nervous system
functions of adrenaline
- increases heart beat and blood pressure
- increases blood supply to muscles, which it decreases to skin and visceral organs
- more glucose is released by liver
adrenal cortex
secretes cortisone. there are two types:
1. mineralcorticoids (regulates mineral metabolism)
2. glucocorticoids(regulate carbohydrate, protein, fat metabolism)
3. sex corticoids
function of cortical hormones
- increase blood glucose concentration
- influence fat and protein metabolism
- regulate salt and water balance in the body
- adapt body to stresses
hyposecretion of cortisone
Addison’s disease
loss of energy, skin pigmentation, loss of weight, hypoglycemia, sensitivity to cold and pain
hypersecretion of cortisone
Cushing’s syndrome
obesity, hyperglycemia, osteoporosis, weakness, salt and water retention
pancreas as duct and ductless
duct: secrete pancreatic juice into duodenum for digestion
ductless: special groups of hormone secreting cells called ISLETS OF LANGERHANS which produce insulin, glucagon, somatostatin (by beta, alpha, delta cells)
insulin
checks rise of sugar level in blood by:
1. promotes use of glucose by body
2. stimulates deposition of extra glucose of blood as glycogen in liver
undersecretion of insulin
diabetes mellitus/ hyperglycemia
1. high concentration of sugar in blood
2. urine has sugar
3. feels thirsty because of loss of water from urine
4. loss in weight
oversecretion of insulin
- low sugar/ hypoglycemia
- brain may enter coma
glucagon
stimulates breakdown of glycogen in the liver to glucose, raises sugar level
location of thyroid
bilobed gland situated in front of neck just below larynx
hormones by thyroid gland
thyroxine
calcitonin
thyroxine
- regulates basal metabolism (rate of cellular oxidation resulting in heat production at rest)
undersecretion of thyroxine
Hypothyroidism
1. simple goitre: due to less iodine
2. cretinism: affects growth of children showing dwarfism and mental retardation. due to degeneration of thyroid
3. myxoedema: sluggish, swelling of face and hands
oversecretion of thyroxine
exophthalmic goitre: causes protrusion of eyes, swelling in neck, more metabolism, rapid heart beat, shortness of breath
location of pituitary gland
small projection which hangs from the base of the mid brain below hypothalamus
lobes of pituitary gland
anterior
posterior
define intermediate lobe
the front part of the posterior pituitary is different from the rest of the lobe. almost absent in humans but much larger and more functional in some lower animals
hormones from anterior pituitary
- growth hormone (somatotropin)
- thyroid stimulating hormone
- gonad stimulating hormone (testes and ovaries)
- adrenocorticotropic hormone (adrenal cortex)
oversecretion of GH suddenly in an adult
excessive growth of hormones in the face, and in hands and feet
large nose and thick lips
aka ACROMEGALY
hormones from posterior pituitary
- antidiuretic hormone/vasopressin
- oxytocin (contraction of uterus, milk ejection)
ADH function
constricts blood vessels
rise in BP
acts on kidney increasing reabsorption of water from tubules
deficiency causes diabetes insipidus- urination is frequent and copius
