Endocrine system Flashcards
What are the functions of the endocrine system
The glands of the endocrine system produce chemical messengers or hormones, which are involved in the regulation of various other functions.
The endocrine system works very closely with the nervous system to maintain homeostasis
What are target cells
Special cells that possesss receptors needed to bind and “read” hormonal messages
What is the control center of the endocrine system
hypothalmus
what are hormones
hormones are chemical messengers released by the endocrine glands and transported by the bloodstream to target cells in other tissues, affecting the target cell’s metabolism
What are the actions of hormons on their target cell
Increase the uptake of particular substances
Alter the target cell’s structure in some way
Influence cell metabolism
What are the functions of the hypothalamus
- Body temperature and salt water balance
- Adrenal medulla through sympathetic nervous system
- Secretion of pituitary gland and peripheral endocrine organs such as adrenals, gonads and thyroid
How does the hypothalamus control the anterior pituitary
by producing hypothalamic-releasing and hypothalamic-inhibiting hormones.
Using thyroid releasing hormone as an example, show how the hypothalmus controls the anterior pituitary gland
TRH stimulates the anterior pituitary to secrete thyroid-stimulating hormone, and TIH inhibits it from secreting thyroid-stimulating hormone. (TSH)
What are the two lobes of the pituitary gland and their resepctive functions
Anterior lobe, where hormones “turn on” endocrine glands or support other organs
Posterior lobe, which contains unmyelinated axons of hypothalamic neurons and stores and releases hormones that are produced in the hypothalamus
What are the hormones that the anterior pitutory gland produces
ACTH (adrenal)
TSH (thyroid)
PRL (Prolactin)
GH (growth)
LH (sexual hormone)
FSH (sexual hormone- follicle stimulating hormone)
All the pretty girls love foxes
What are the hormones the posterior lobe of pituratry produces
OXT
ADH
The hormone that is neither here nor there, melanocytes
Is melanocyte stimulating hormone under anterior or pitutary gland-
What conditions can too much growth hormones cause
Gigantism
Acromegaly
What does a deficency of ADH result in
diabetes insipidus
- results in large amount of urine, resulting in severe dehydration and loss of important ions
- can be corrected with administering ADH.
What hormones does the thyroid gland produce
T3, T4 and calcitonin
What are the physiologic effects of thyroid hormones
Calorigenic effect
- cell consumes more energy resulting in increased heat generation
- is responsible for strong, immediate, and short-lived increase in rate of cellular metabolism
Growth
Development
- essential for development of the fetal and neonatal brain
Important for nomral functioning of cardiovascular, nervous and reproductive system
What does hyperthyroidism result in
A goiter may be formed and eyes protrude from edema in eye socket tissues
Symptoms: hyperactivity, nervouness and irritability
Lab test: T3 and 4 increased, TSH decreased, TRH decreased
Treatment: Surgical removal or destruction of a portion of the thyroid by radioactive iodine
What does hypothyroidism result in children
Congenital hypothyroidism (Cretinism)
- underdevlopment of thyroid at birth, intellectual disability may result if thyroid hormone therapy is not begun in the first 2 months
What does hypothyroidism result in adults
Myxedema
Symptoms: lethargy, weight gain, loss of hair, slower pulse, cold intolerance, lowered body temperature
Lab Test: T3 and 4 decreased in blood, TSH and TRH increased
Treatment: administration of thyroid hormones restores normal function
What is the parathyroid glands function
Produces PTH (parathyroid hormone) to increase calcium ion concentration in body fluids
What does the adrenal gland consist of
Adrenal cortex which stores lipids and consits of corticosteroids
Adrenal medulla controled by sympathetic division of ANS
- produces adrenaline, metabolic changes persist for several mintues
Give an example of mineralocorticoids and when secretion takes place
Example: Aldosterone
- stimulates conservation of sodium ions and elimination of potassium ions
- increases sensitivity of salt receptors in taste buds
Secretion responds to:
- drop in blood sodium (Na+), blood volume, or blood pressure
- rise in blood potassium (K+) concentration
Give an example of mineralocorticoids and its functions
Secretion is controlled by ACTH.
- examples: cortisol, corticosterone, and cortisone
Functions:
- regulate carbohydrate, protein, and fat metabolism.
- raise the blood glucose level.
- active in the stress response and the repair of damaged tissues.
- relieve swelling and pain from inflammation.
Name the three type of cells in the pancreas and where they are located
In the islets of Langerhans
A cells (glucagon)
B cells (insulin)
D cells (somatostatin)
how does pancrease differet from other endocrine organs
pancrease is not under pituitary control and responds directly to changes in blood glucose levels
when is insulin secreted and what does it do
When blood glucoses levels are high, stimulates the uptake of glucose by cells (liver, muscle and adipose cells)
When is glucagon secreted and waht does it do
Secreted when blood glucose levels are low
Stimulates the liver to break down glucogen to glucose, promotes the use of fat and protein in preference to glucose and adipose cells break down fat to glycerol and fatty acids
To raise blood glucose level
When does diabetes mellitus take place (IMPT)
DM is due to either hyposecretion of insulin or decreased sensitivity of insulin receptors
What are the symptoms of diabetes (IMPT)
Polyuria (frequent urination)
Polyphagia (constant hunger)
polydypsia (drinks a lot of water as one is always thirsty)
Fatigue and weight loss
Glycosuria: Glucose is excreted in the urine
Hyperglycemia: An excess of glucose in the blood
What are the endocrine tissue of ther systems
Intestines (promote digestive activites)
Kidneys (produce hormones calcitriol and erythropoietin n enzyme renin that increases bv n bp)
heart (produce ANP which reduces bp n bv)
thymus (produce thymosisns)
Adipose tissue secretions (leptin)
Gonads
Give examples of the hormones that testes produce
androgens:
- Testosterone,
promotes production of functional sex cells (sperm)
- Maintain secretory glands of male reproductive tract
- Determine secondary sex characteristics
Affects metabolic activities: protein synthesis, muscle growth
- produces aggressive behavorial responses
- affects embryonic development of sexual organs
Nurse cells secrete inhibin
- maintain sperm productions at normal levels
What does the ovaries produce
Follicle cells (by FSH) produce estrogens
- support maturation of oocyte to ovum
- stimulate growth of uterus lining
- development of secondary sexual characteristics.
After ovulation estrogens and progesterone realeased,
- Progesterone: speeds up movement of fertilized eggs along uterine tubes, prepares uterus for arrival of developing embryo, causes mammary gland to enlarge
What are the four type of effects of hormone interactio
Antagonistic (opposing) effects
Synergistic (additive) effects
Permissive effects
- one hormone is necessary for another to produce effect
Integrative effects
- hormones produce different and complementary results
What do homone interaections control
Normal growth
Reaction to stress
Alteration of behavious (puberty)
Effects of aging (less responsive)
What does growth homones contribute to in children and adults
In children, i t support muscular and skleltal development
In adults, it maintains normal blood glucose concentrations and mobilizes lipid reserves
What does PTH and calcitriol hormone play a part in
- Promote absorption of calcium salts for deposition in bone
- Inadequate levels cause weak and flexible bones
What does reproductive hormones play a role in
Androgens in males, estrogens in females
Stimulate cell growth and differentiation in target tissues
Produce gender related differences in
- skeletal proportions
- secondary sex characteristics
What happens to hormones during aging
Most hormones remain the same throughout adulthood
Exceptions are the reproductive hormones where changes to target organ receptors more likely to occur through reduced sensitivity
