ANAPHY FINALS ENDO Flashcards
Chemical messengers used by endocrine system
Hormones
Most are released into blood
Hormones
Types of chemical signaling
Paracrince signaling
Autocrine signaling
Endocrine signaling
Used by neurons and the nervous system
Neurotransmitters
Hormone affects neighboring cells
Paracrine signaling
Hormone affects same cell that released it
Autocrine signaling
Hormone travels through blood to affect cells throughout body
Endocrine signaling
What is the second messenger system?
- Hormone binds to receptor in cell membrane
- G protein is activated
- G protein activates adenylyl cyclase
- Adenylyl cyclase converts ATP to cyclic adenosine monophosphate (cAMP)
- cAMP activates protein kinases
- Protein kinases phosphorylate proteins
- Phospholyrated proteins cause change
- Amplification allows a small amount of hormone to cause significant change
- Phosphodiesterase (PDE) breaks down cAMP [Quickly stops internal cellular changes]
To note: other second messenger systems may use calcium ions as a second messenger systems
Released in response to high blood osmolarity [the solute concentration of blood]
Antidiuretic hormone
How does antidiuretic hormone conserve body fluid?
By increasing water reabsorption by kidney
Urine becomes darker
Can also cause constriction of blood vessels
Antidiuretic hormone
Leads to overall increase in pressure
Antidiuretic hormone
Antidiuretic hormone’s release is inhibited by?
Drugs like alcohol
Higher amounts of urine is produced
Growth hormone promotes growth of epiphyseal plate during childhood leads to:
Elongation of bones
Decreased stature due to decreased secretion of GH during childhood
Pituitary dwarfism
Substantially increased height due to excessive GH secretion during childhood
Gigantism
Excessive GH secretion during adulthood
Cause increased growth of cartilage leading to larger hands, feet, and ears
May cause cardiovascular complications due to diabetogenic effect
Acromegaly
The thyroid gland is located—
Anterior to Trachea
Inferior to larynx
The thyroid gland has two lobes connected by—-
Isthmus
Spherical units of thyroid [internal cavity filled with colloid]
Thyroid follicles
Thyroid hormone (TH) made by—
Follicular cells
It is stimulated TSH from anterior pituitary gland
Follicular cells bind iodine to ____ in colloid
Thyroglobulin proteins
Intermediaris are combined to form—
T3 (triiodothyronine) and T4 (tetraiodothyronine)
T4 is commonly known as thyroxine
This remains in colloid until needed
Hormones
It stimulates release of T3 and T4 from follicular cells when necessary
TSH (Thyroid-stimulating hormone)
It regulates TH secretion
Negative feedback
Low levels of TH stimulates—
TRH release from hypothalamus
It stimulates release of TSH from anterior pituitary
TRH
It stimulates release of TH from thyroid gland
TSH
Functions of Thyroid Hormones
- Increase basal metabolic rate (BMR) —causing every cell to increase production of ATP
- Promote protein synthesis
- Increase effectiveness of epinephrine and norepinephrine
- Increase body temperature—by the heat given off by due to ATP production
- Required for adequate growth and development of skeletal and nervous tissue in childhood
Functions of Thyroid Hormones
- Increase basal metabolic rate (BMR) —causing every cell to increase production of ATP
- Promote protein synthesis
- Increase effectiveness of epinephrine and norepinephrine
- Increase body temperature—by the heat given off by due to ATP production
- Required for adequate growth and development of skeletal and nervous tissue in childhood
Enlarged thyroid ; caused by accumulation of colloid
Goiter
Insufficient production of thyroid hormones ; may lead to weight gain and cold intolerance
Hypothyroidism
Excessive production of thyroid hormones ; may lead to weight loss and increased body temperature
Hyperthyroidism
Secreted by parafollicular cells and secreted in response to elevated blood calcium levels
Calcitonin
Calcitonin decreases blood calcium levels by
- Inhibits osteoclast activity and stimulates osteoblast activity
- Decreases calcium absorption by the intestine
- Increases calcium loss in urine
It plays a role in many biological processes
Calcium
It’s regulated by hormones
Levels
Calcitonin from thyroid and parathyroid hormone from parathyroid glands work—
Antagonistically to regulate calcium levels
Located on the posterior of thyroid gland
Parathyroid glands
The function of this is unknown
Oxyphil cells
It secretes parathyroid hormones
Chief cells
It’s secreted in response to low calcium levels and it increases blood calcium levels by stimulating osteoclast that breakdown bone matrix releasing calcium
Chief cells
It inhibits osteoblast and stimulate calcitriol production to increase absorption of dietary calcium
Parathyroid glands
Excessive secretion of PTH leads to excessive bone resorption and leads to increased blood levels of calcium
-decreased bone density, leading to increased fractures
-reduced responsiveness of nervous system
-increased calcium deposits in tissues and organs
Hyperparathyroidism
Insufficient production or secretion of PTH
- leads to low blood levels of calcium, causing muscle twitching, cramping, convulsions, or paralysis
Hypoparathyroidism
It has triangular glands on top of each kidney and is covered by capsule
Adrenal Glands
The adrenal glands is divided into two
Adrenal cortex (superficially) and Adrenal medulla (deeper)
Adrenal cortex has three zones
Zona glomerulosa
Zona fasciculata
Zona reticularis
Most superficial region of adrenal cortex and secretes mineralcorticoid
Zona glomerulosa
What is the main mineralocorticoid of Zona glomerulosa?
Aldosterone
It increases sodium and water reabsorption by kidney and increases blood pressure
Aldosterone
It is involved in renin-angiotensin-aldosterone system (RAAS)
Zona glumerulosa
Intermediate region of adrenal cortex and secretes glucocorticoids
Zona fasciculata
The main glucocorticoids of zona fasciculata
Cortisol
It is released in response to stress, and the release is stimulated by ACTH ; suppresses immune system
Cortisol
Cortisol stimulates breakdown of stored nutrients for energy by (3)
Glycogenolysis
Lipolysis
Gluconeogenesis
Deepest region of adrenal cortex and secretes androgens
Zona reticularis
Androgens are
Male sex hormones
The main androgen secreted is—
Dehydroepiandrosterone (DHEA)
Supplements testosterone in males and promotes libido in women
Zona reticularis
The ______ releases epinephrine and norepinephrine—which are collectively called _______
Adrenal medulla ; catecholamines
Catecholamines are produced by—
Chromaffin cells
These are considered hormones when released into blood and considered neurotransmitters when they are released into synapse
Catecholamines
It releases results in fight or flight response in the sympathetic nervous system
Adrenal medulla
Hypersecretion of cortisol
Results in hyperglycemia and lipid deposits around face and neck
Moon-shaped face, buffalo hump, rapid weight gains
In risk of type 2 diabetes
Cushing’s disease
Hyposecretion of cortisol
Results in hypoglycemia and low blood levels of sodium (hyponatremia)
Addison’s disease
It is located within abdomen posterior to stomach and has both endocrine and exocrine glands
The pancreas
Exocrine function (in the pancreas) is—
To secrete digestive enzymes
What are the endocrine cells in the pancreatic islets:
Alpha cells
Beta cells
Delta cells
PP cells
Secretes glucagon
Alpha cells
Secretes insulin
Beta cells
Secretes somatostatin
Delta cells
Secretes pancreatic polypeptide
PP cells
Insulin lowers blood glucose by
Stimulating uptake cells
Glycogenesis
Lipogenesis
Glucagon increases blood glucose by
Glucogenolysis
Lipolysis
Gluconeogenesis
Stimulates glucose uptake in cells and primary target cells include skeletal muscle cells and adipocytes
Insulin
Binding of insulin leads to—
Increased number of glucose transporters (GLUT) in membrane of target cells
Located within mediastinum, superior to heart and is the site of T lymphocyte maturation within the immune system
The Thymus
It is more active in childhood and decreases in size with age
T lymphocyte
What does the thymus secrete that aids in development and differentiation of T lymphocytes
Thymosins
It secretes atrial natriuretic peptide (ANP)
Heart
The two functions of ANP
Decreases blood pressure in response to increased blood volume or increased blood pressure
Increases sodium and water loss by the kidneys (via urine) to decrease blood volume and blood pressure
The Gastrointestinal tract has
Endocrine cells located in walls of stomach and small intestine
It has hormones that aids in digestion
It stimulates the release of hydrochloric acid by stomach
Gastrin
Other hormones (in the gastrointestinal tract) aid in regulation of
Glucose metabolism
Produces renin that is involved in the renin-angiostenin-aldosterone system (RAAS)
The Kidney
Secretes calcitriol that aids in regulation of calcium homeostasis
Kidneys
The kidney produces ____ that stimulates the production of red blood cells
Erythropoietin (EPO)
Hormones found in the adipose tissue are called _____ and are involved in metabolism and nutrient storage
Adipokines
The adipose tissue secretes the hormone _____ that helps reduce appetite and binds to neurons within brain to cause the feeling of satiety after a meal
Leptin
The adipose tissue secretes the hormone ______ that reduces cellular insulin resistance
Adiponectin
Is involved in production of vitamin D
Skin
Why does the skin absorb UV radiation? It is converted by?
To convert cholesterol into inactive vitamin D
Liver and kidneys
It is involved in absorption of dietary calcium and immune functions
Active vitamin D
The _____ secretes insulin-like growth factor (IGF) in response to GH
Liver
The liver produces ______ , a precursor to the angiostenin, a hormone involved in increasing blood pressure
Angiotensinogen
The liver secretes ______ , a hormone that stimulates platelet production
Thrombopoietin
The liver secretes _____ that regulates iron levels
Hepcidins
