Lecture 6 - Endocrine Glands Flashcards
what is the role of the hypothalamus and pituitary glands ?
the hypothalamus acts as an interface between nervous and endocrine glands
the pituitary gland is located at the base of the brain
Anterior pituitary - secrets hormones under the influence of releasing hormones produced by the hypothalamus - hormones will travel from hypothalamus via the hyphophyseal portal system
will produce thyroid stimulating hormones (TSH) among others. Growth hormone for the bones
Posterior Pituitary - Releases two hormones produced in the hypothalamus - neurosecretory axons from the hypothalamus extend directly into the PP - ADH (kidneys) and oxytocin (ovaries and mammaries) are the hormones
what are the pituitary hormonesand where are they produced ?
Know a couple
Posterior Pituitary - ADH (kidneys water resorption) and oxytocin (ovaries and mammaries) are the hormones
Releaser—Hormone—Gland—2ndry hormone—-Impact
TRH ——TSH——Thyroid—–T3 and T4—Metabolic rate
CRH—–ACTH—–Adrenal—-Cortisol—–Stress response
also secretes LH (luetinizing horomone) and FSH (follice stimulating hormone) and GH (growth hormone)
all releasing hormones are produced in the hypothalamus then transferred via the hyphophyseal portal system - they will trigger the release of the desired hormones
what is the structure of the thyroid gland ?
made of spherical folices (1 unit) - simple cuboidal epithelium - conatins colloid - stores thyroglobulin - used to synthesise T3 and T4
the follicular cells produce T3 and T4
Para follicular cells produce calcitonin
hormones are secreted into capilliaries
how does the thyroid hormonal system work ?
what are the disease states ?
anterior to trachea - butterfly shape
T3 and T4 are the thyroid hormones
T3 and T4 will increase metabolic rate, stimulate catabolism
Hypothalamus produces TRH - stimulates TSH release in the anterior pituitary - TSH will stimulates release of T3 and T4 in thyroid - will increase metabolism - T3/4 will also inhibit the hypothalamus and pituitary to stop TSH/TRH release (a negative feedback loop)
Hypothyroidism (hasimoto’s) - TSH is high and T3/T4 is low - immune cells attack T3/T4 - hair loss , puffy face
hyperthyroidism (graves disease) - TSH is low - T3/T4 is high - there is a TSH mimicer competing - buldged eyes and enlarged thyroid
thyroid diseases are are consquence of antibodies preventing the systems from working
what are the parathyroid glands ?
4 glands on the posterior of the thyroid
contains lots of adipose tissue
monitor Ca2+ plasma concentrations
Cheif cells are producing parathyroid hormone (PTH) - when Plasma Ca2+ is low - will increase Ca2+ reabsorption from the kidneys and bone
also has oxyphil cells
explain structure and purpose of the adrenal glands?
what hormones does it produce and their effects
adrenal glands sit ontop of kidneys
structure is made of layers
Capsule —- Cortex —- Medulla
Zona glomerulosa - produces aldosterone ect
Zona fasiculata - produces cortisol ect
Zona reticularis - glucocorticoids and a little androgens, estrogen
Medulla - contains chromaffin cells (modified neurons) which produce adrenaline and noradrenaline
the hypothalamus will release CRH - cortisol release hormone
will stimulate the antierior pituitary to release ACTH
will stimulate the adrenal cortex to release cortisol
cortisol will stimulate many tissues involved in stress response
cortisol will inhibit anterior pituitary and the hypothalamus (negative feedback)
explain the structure and function of the pancreas
location - behind the stomach
structure -made of lobules - contains :
connceted by intercalated ducts to pancreatic duct, will join the bile duct - lined with cuboidal epithelial cells
aciniar glands
islets of langerhans
blood vessels
contains many zymogen granules - contain digestive enzymes
99% exocrine duct glands - digestive enzmyes eg pancreatic amylase, lipase, trypsin, chromotrypsin, carboxypeptidase, elastase into duodenum
1% endocrine ductless- hormones from the islets of Langerhans - alpha cells produce glucagon (glucose breakdown hormone) and beta cells produce insulin (storage hormone)
outline the types of hormones
glycoproteins - insulin, glucagon, ACTH,PTH
Steroid horomones - oestrogen, androgens, aldosterone, cortisol
Amino acid derivative catecholamine - adrenaline and noradrenaline
amino acid derivative thyroid hormones- T3 and T4
what is the role of the hypothalamus ?
just get some of these
Hypothalamus deals with:
– Thermoregulation, panting, sweating, shivering, etc.
– Plasma osmolality via osmoreceptors
– Heart rate, blood pressure
– Feeding, satiety, regulation of the gastrointestinal
ttract
– Circadian rhythms, wakefulness, sleep (nerves from retina)/ hormones (melatonin from pineal gland)
– Stimuli from the autonomic nervous system (both sympathetic and parasympathetic)
– Emotion, sexual behaviour, mood
– Lactation (suckling/baby crying)
• Hypothalamus produces
– Vasopressin (ADH) and oxytocin that travel to posterior pituitary through nerves
– Six hormones that travel via the hypothalamo-hypophyseal portal system (blood) to the anterior
pituitary.
the portal system is unique as it will form two capilliary beds between artery and vein
look at histology of the different glands - lec 6
do it
what is the stress response that is caused ?
increase respiratory and cardiovascuar rates
greater awareness and congintion
raise BP
