Endocrine System Flashcards
what is homeostasis defined as?
tendency of a system to maintain internal stability
endocrine system (read)
slower rates, hormones, longer distances throughout the body
define intrinsic controls
controls regulate factors within a local environment (in an organ)
define exinstric controls
controls regulate factors coordinating body systems (initiated outside of an organ)
define feedforward
control signals sent to a part of the body or other system in order to prepare it for future motor activity or expected sensory input
define feedback
responses made after a change has already been detected
feedback is split into two categories, what are they?
negative and positive
negative feedback
causing a change to be minimized or stopped
positive feedback
increase the change or output
where is thyroxine produced? (hormone)
thyroid gland
what is the role of thyroid hormones in metabolism?
increasing the rate at which cells convert oxygen and calories into energy. they help control processes like growth, energy and temperature regulation.
what are T3 and T4?
T3: triiodothyronine
T4: thyroxine
what is the normal for blood sugar regulation?
80-120mg/100ml
what hormone is secreted when blood sugar is high
insulin
what is the role of insulin in blood sugar regulation?
insulin is secreted by the pancreas to allow glucose to enter body cells, returning blood sugar levels back to homeostasis
what happens when blood sugar is too low?
the pancreas secretes glucagon
what does glucagon do in the body?
glucagon breaks down glycogen stores into glucose, increasing blood sugar levels
what are glycogen stores and where are they found?
glycogen stores are stored glucose, found in the liver and large muscle groups
what are the two types of cells in the pancreas involved in blood sugar regulation?
- alpha cells: secrete glucagon
- beta cells: secrete insulin
what is the purpose for glucose in the body?
glucose will provide energy for the body cells
what is the difference between glucose and glycogen?
glucose: simple sugar in the blood
glycogen: stored form of glucose in liver and muscles
what are the two parts of the adrenal gland involved in the stress response?
the adrenal medulla (internal) and adrenal cortex (external)
what hormone is released in response to stress by the pituitary gland?
ACTH (adrenocorticotrophic hormone)
what does the adrenal medulla produce during short term stress?
epinephrine and norepinephrine
what hormone is affiliated with adrenaline?
epinephrine
list six effects of epinephrine and norepinephrine during short term stress
- increased heart rate
- increase blood pressure
- increased blood flow to heart and muscles
- increased breathing rate
- increase of blood glucose
- increased rate of cell resp.
what is produced by the adrenal cortex during long term stress?
mineralocorticoids such as aldosterone
what role does aldosterone play during long term stress?
helps kidneys reabsorb sodium and water which then maintains the blood pressure
where is the pituitary gland located?
base of the brain
where is hypothalamus located?
in the brain, below thalamus, and above pituitary gland
why is the pituitary gland referred to as the master gland?
it controls other glands and secretes multiple important hormones
what does the posterior pituitary gland do?
stores hormones
name two hormones stored in the posterior pituitary gland?
oxytocin and ADH (antidiuretic hormone)
what role does oxytocin play in the body?
oxytocin is involved in uterine contractions during childbirth and milk ejection during breastfeeding
what does ADH do?
helps to regulate water balance by promoting water reabsorption within the kidneys
what is the role of the anterior pituitary gland?
produces and secretes hormones
list six hormones secreted by the anterior pituitary gland?
- hgh (human growth hormone)
- tsh (thyroid stimulating hormone)
- fsh (follicle stimulating hormone)
- lh (luteinizing hormone)
- acth (adrenocorticotrophic hormone)
- prl (prolactin)
what is the function of the glucocorticoids?
help metabolize proteins and fats
how do glucocorticoids affect the immune system
suppress immune cell activity
what does HGH target and its function?
it targets heigh, bone and muscle developpement, and its function is to stimulate fat and sugar metabolism
what does TSH target and its function?
targets the thyroid gland, and its function is to control metabolism and affect energy and growth
what does ACTH target and its function?
it targets the adrenal gland and it controls the stress hormones
what does FSH target and its functions?
targets the ovaries and testes and its function is to produce ovarian follicle production and sperm maturation
what does LH target and its function?
it targets ovaries and testies, initiates ovulation, formation of the corpus luteum and stimulates production of testosterone
what is the corpus luteum?
a mass of cells that forms in an ovary
what does PRL target and its function?
targets the breasts and controls and sustains milk production
what does oxytocin target and its function?
targets uterus and breasts and stimulates uterine contraction and stimulates secretion of milk
what does ADH target and its function?
targets the kidneys and controls the reabsorption of water
how does sexual reproduction differ from asexual reproduction?
sexual involves fusion of gametes creating new gene combinations leading to genetic diversity
why is genetic diversity important?
provides for evolution and natural selection, allowing for species to adapt and survive
what are the primary reproductive organs called and what do they produce?
- gonads (testes in males, ovaries in females), produce gametes and secrete sex hormones (testosterone, estrogen and progesterone)
what controls the onset of puberty?
- hypothalamus (releases GNRH, gonadotrophin-releasing hormone)
- anterior pituitary: releases FSH and LH
what is the role of FSH in males and females?
in males, FSH stimulates sperm production. in females it stimulates follicle developpement in the ovary
what is the role of LH in males and females?
in males, it stimulates testosterone production and sex organs. in females, it stimulates ovulation and follicle release
how is Fsh production regulated in males?
testosterone causes sertoli cells in testes to produce inhibin, which inhibits FSH production through negative feedback
how do estrogen and progesterone regulate the menstrual cycle?
at start of cycle, estrogen provides positive feedback, increasing LH secretion. after ovulation, estrogen and progesterone provide negative feedback, inhibiting the hypothalamus and pituitary.
what secondary sex characteristics influenced by estrogen and testosterone?
- hair growth
- genital maturation
- shoulder width and muscle mass increase (males)
- wider hips and fat distribution in butt and breasts (females)
how does testosterone affect the voice and skin in males?
enlarges the larynx and thickens vocal cords (deeper voice) and increases sebaceous gland activity leading to thicker secretions (acne, etc)
what mental changes are associated with testosterone during puberty? (males)
increased aggression and sex drive