Endocrine System Flashcards
Steroid hormones
hormones synthesized from cholesterol
Signal transduction
chemical communication
Steroid hormone diffuses across ___
cell membrane
Once inside cell, steroid hormone then binds to ____
specific receptors protein inside cell
Receptor
hormone complex binds to target DNA
Steroid hormone activates ___
expression for specific target genes
Non-steroid hormones
hormones synthesized from protein
Signal transduction
Bind to receptor on surface of cell membrane
G protein activates adenylate cyclase
ATP converted into cyclic adenosine monophosphate (cAMP)
cAMP activates protein kinase enzymes
Specific target proteins activated by phosphorylation
Pituitary gland
attached to the hypothalamus at base of the brain
Growth hormone (GH)
stimulates cells to divide
Prolactin (PRL)
stimulates milk production
Thyroid-stimulating hormone (TSH)
controls thyroid
Adrenocorticotropic hormone (ACT H)
controls adrenal cortex
Gonadotropins
hormones that affect reproductive organs
Follicle
stimulating hormone (FSH)
Follicle (in females)
stimulates development of ovarian follicles
Follicle (in males)
stimulates production of sperm
Luteinizing hormone (LH) in females
triggers ovulation
Luteinizing hormone (LH) in males
stimulates production of testosterone
Antidiuretic hormone (ADH)
causes kidney to conserve water
Diuretic
chemical that increases urine production
Antidiuretic
decrease urine production
Oxytocin (OT)
contracts smooth muscle in uterine wall
contracts cells in milk-secreting glands
Thyroid gland
attached in between larynx + trachea
Control basal metabolic rate (BMR)
amount of calories consumed at rest
- Activates genes for cellular respiration
- Regulates body heat
Goiter
enlarged, protruding thyroid gland occurs from iodine deficiency
Calcitonin
regulates calcium + phosphate in blood
Adrenal glands
sit on top of each kidney
Adrenal medulla
inner layer
Epinephrine
adrenaline
Norepinephrine
stress hormone
Epinephrine effects
Force cardiac muscle contractions to increase heart rate Increase breathing rate Increase glucose levels in blood Elevate blood pressure Decrease digestive activity
Adrenal cortex
outer layer
Aldosterone
mineralocorticoid
Aldosterone does ___
Cause kidneys to conserve sodium ions + exert potassium ions
Leads to water retention by osmosis to maintain blood volume/blood pressure
Cortisol
glucocorticoid
Cortisol stimulates ____
liver cells to synthesize glucose from circulating amino acids + fatty acids - increases blood glucose levels
Cortisol maintains ___
blood glucose at normal levels between meals
Under stress ____
the set point is elevated to release more cortisol until stress subsides
Pancreas
posterior to stomach
Pancreatic islets
islets of Lagerhands, secrete hormones into blood stream
Glucagon
- Stimulates liver to break down glycogen
- Raise blood sugar
- Prevent hypoglycemia
- Low blood glucose between meals or during exercise
Insulin
- Stimulates liver to form glycogen from glucose
- Promotes glucose uptake by adipose, cardiac + skeletal muscles
- Decreases blood sugar levels
- Stimulates adipose cells to synthesize and store fat
The actions of glucagon and insulin are paired to ___
regulate blood sugar
Nerve cells are particularly sensitive to ___
blood glucose levels
Pineal gland
attached to upper part of thalamus
Melatonin
regulates circadian rhythm
Release of melatonin is triggered when ____
retinas receive No light input
Melatonin increases in ___
the dark, decreases in light
Melatonin maintains ___
- day/night cycle, sleep/wake pattern
- seasonal cycles, fertility patterns in animals
Thymus
posterior to sternum between lungs
The thymus is relatively ___
large + young, shrinks w/ age
Thymosins
affects production and maturation of WBC
Testes
produce testosterone
Ovaries
produce estrogen +progesterone
Placenta
produce estrogen progesterone, gonadotropin
Physical stress
injury, disease, extreme temperature, decreased O2, heavy exercise
Psychological stress
emotional distress, personal loss, social interactions
Stress response
general adaptive syndrome
Immediate “alarm” stage
epinephrine, norepinephrine
Long-term “resistance” stage
- Hypothalamus secretes corticotropin-releasing hormone (CRH)
- Stimulates anterior pituitary to secret Adrenocorticotropic hormone (ACTN)
- Travels blood stream to adrenal glands
- Stimulates adrenal cortex to release cortisol
Exhaustion
chronic health effects:
- Decreased number of lymphocytes
- Lower resistance to infection + cancer
- Increase risk of high blood pressure, atherosclerosis, ulcers