Homeostasis Flashcards
What is homeostasis?
Homeostasis is the body’s internal system adjusting to changing conditions in the internal/external environment
All homeostatic systems have three components. What are they?
- Sensor (senses stimulus)
- Control centre/integrator (usually the brain)
- Regulator/ effector that carries out the response
What kind of receptors in the skin detect a decrease in temperature?
Thermoreceptors
Breakdown of thermoreceptors:
- Send message to integrator, ___________ to secrete ________.
- Blood carries _____ to the _____ gland.
- _____ signals the pituitary gland to secrete _______ into blood.
- Blood carries _____ to the thyroid.
- Thyroid produces and secretes ______.
Breakdown of thermoreceptors:
- Send message to integrator, hypothalamus to secrete TRH (thyroid releasing hormone).
- Blood carries TRH to the pituitary gland.
- TRH signals the pituitary gland to secrete TSH (thyroid stimulating hormone) into blood.
- Blood carries TSH to the thyroid.
- Thyroid produces and secretes thyroxine.
Thyroxine tells all body cells to increase _______ metabolism, increasing ________ in the body.
glucose metabolism, heat production (temperature)
What is a dynamic equilibrium?
A condition that remains stable with fluctuating limits
In regards to TRH and TSH, which part of the pituitary are they involved in?
(anterior or posterior)
Anteriori pituitary
When the body becomes too _____, ________ feedback tells the hypothalamus to slow the production of _____.
hot (too much thyroxine), hypo slows production of TRH
There are two types of thyroxine, T3 and T4. What is the diff between the two?
T4: four iodine atoms and T3: three iodine atoms
What is the main characteristic of hyperthyroidism?
Too much thyroxine in the blood.
In hyperthyroidism, ________ is too high. This may cause which 3 symptoms?
Metabolism is too high.
Symptoms:
1. loss of weight
2. excessive sweating
3. bulging eyes (Grave’s disease)
4. goiter (swelling of the thyroid)
What is an autoimmune disease? What are autoimmune diseases related to hypo/hyper?
Condition in which the body’s immune system mistakes its own healthy tissues as foreign and attacks them
Hyper: Graves
Hypo: Hashimotos
What are three causes of Hyperthyroidism ?
- Cancer
- Thyroiditis (infection of thyroid)
- Thyroid Stimulating Antibody that kills healthy tissue (Grave’s disease)
Why is radioactive iodine used to treat hyperthyroidism?
Radioactive iodine kills thyroid cells such that less thyroxine is produced
What Hypothyroidism? What are 3 symptoms?
A condition in which the thyroid does not produce enough thyroxine (levels in blood are too low)
- Weight gain
- Feeling cold
- Goiter
What are 3 causes of hypothyroidism and a treatment option?
Causes:
1. Treatment of hyper can cause hypo
2. Hashimoto’s
3. Pituitary disorder (not enough TSH)
Treatment: thyroxine supplements
In both hypo and hyper thyroidism, a goiter forms. Why?
Hyper: thyroid produces excess ______
Hypo: ______ levels are too high due to low levels of thyroxine. No _______ feedback to ________.
Hyper: thyroid produces excess thyroxine
Hypo: TSH levels are too high due to low levels of thyroxine. No negative feedback to hypothalamus.
Thermoregulation is how the body controls _______.
Temperature
What is the difference between how endotherms and ectotherms regulate temperature?
Endotherms: maintain body temp w internal mechanisms (ex. shivering, dilation of vessels in humans)
Ectotherms: absorb therm energy from environment (fish, reptiles)
Which region of the brain controls temp?
Hypothalamus
What is the difference between peripheral and central nerve receptors?
Central receptors: arteries/organs monitor core temp (slightly higher)
Peripheral receptors: in skin monitor skin temp
What is the difference between skeletal and smooth muscle?
Skeletal: can contract
Smooth: non-contractable (rib/diaphragm)
What is the difference between positive and negative feedback loops?
Negative loop: wants to offset the stimulus
Positive loop: wants to increase the effect of the stimulus
How do negative feedback loops control temp? (3 steps)
- Cold temp stimulates the thermoreceptors in skin
- Send message to hypothalamus to integrate
- Hypothalamus tells the sweat glands to sweat
How does a negative feedback loop return stop? Why can’t one sweat forever?
Eventually sweat produced causes the body to become too cold. It dips below the set point. This serves as a new stimulus
Positive feedback loops move a _________ variable away from a ______ state. This causes the process to move _____ {speed} and it STOPS
controlled variable away from a steady state. It is quick
Growing a baby, there are high levels of the hormone ________. Upon a decrease, _________ start in the womb.
progesterone, contractions
Small contractions move baby towards opening of the uterus, ______. This causes _______ to be released, which targets the ______ and causes stronger contractions.
cervix, oxytocin, uterus
When temp falls below the set point in a home, thermostat (_______) switches on furnace (________). When temp is above set point, thermostat turns off furnace.
sensor, effector (regulator)
What is osmotic pressure? (pressure results from…)
Pressure that results from a difference in solutes between 2 sides of a permeable membrane
Which process regulates osmotic pressure of bodily fluids and cells?
Osmoregulation
Hyposmotic solutions have a _______ concentration of water. Hyperosmotic solutions have a _____ concentration of water (more solute).
hyposmotic: higher { } of water
hyperosmotic: lower { } of water
Deamination is the process by which an _______ group is ______ from an amino acid. The amino group is converted to _______. The rest of the amino acid is oxidized to produce _______.
Deamination is the process by which an amino group is removed from an amino acid. The amino group is converted to ammonia. The rest of the amino acid is oxidized to produce energy.
Ammonia is ______ (toxic/non-toxic). It combines in urea to form a less toxic form. It is secreted by which creatures?
Ammonia is toxic.
Animals that produce urea include mammals, sharks, adult amphibians, etc.
How do mineral salts play a role in osmoregulation?
Salt and sugar creates a concentration gradient that causes pressure. This pressure moves water outside and inside of cells to that they are isotonic
What are three functions of the kidney?
- Remove excess urea from the blood
- Maintain water balance in the blood
- Maintain pH balance in the blood
The renal artery carries fresh blood from the ______ to the kidney.
aorta
The renal vein carries filtered blood from the kidneys to the _______ ____ _____.
inferior vena cava
the renal pelvis connects the kidney to the ________ through which urine goes to the _______.
ureter, bladder
What is the inner layer of the kidney called? the outer layer?
inner: renal medulla
outer: renal cortex
The afferent arteriole supplies blood to kidney, directly to the __________
glomerulus
The efferent arteriole carries _______ blood away from the _________ to the _________ capillaries and eventually _______ vena cava.
The efferent arteriole carries filtered blood away from the glomerulus to the peri tubular capillaries and eventually inferior vena cava.
The proximal tubule connects the _________ ______ to the loop of Henle.
The distal tubule connects the loop of Henle to the __________ duct.
prox: Bowman’s capsule
distal: collecting
What is the glomerulus?
Network of capillaries that perform the first step in the filtration of blood
What are the three steps in urine production?
Filtration, re-absorption, secretion
In filtration, only small things from the ________ (blood) are filtered to the ________ _______ (tubule)
glomerulus (blood), bowman’s capsule (tubule)
In filtration, only small things from the ________ (blood) are filtered to the ________ _______ (tubule). What do these include?
glomerulus (blood), bowman’s capsule (tubule)
- amino acids
- water
- NaCl
- glucose
- Urea
What are 3 things not filtered during filtration?
- Proteins
- Blood cells
- Some water and salts
There are two types of re-absorption. One occurs in the _______ tubule, the other in the loop of ______.
proximal tubule and loop of Henle
How much filtrate is excreted as urine?
1.5 L
Re-absorption in the loop of Henle is when ______ re-enters the blood via _______. As _______ leaves the tubule, the filtrate becomes more concentrated.
Re-absorption is when water re-enters the blood via osmosis. As water leaves the tubule, the filtrate becomes more concentrated.
What leaves the tubule in the descending loop of Henle? What is not permeable?
Water leaves. Ions are not permeable
What leaves the tubule in the ascending loop of Henle? What is not permeable?
Ions (Na+, Cl-). Water is not permeable
Since we are creating a _____ gradient, the ________ is said to be salty.
salt, medulla
_________ reabsorption occurs in the proximal tubule. The nephron _______ transports ______, amino acids and _____ ions back into the blood to be used. Cl- ions follow and enter ______.
Selective reabsorption occurs in the proximal tubule. The nephron actively transports glucose, amino acids and Na+ ions back into the blood to be used. Cl- ions follow and enter passively.
Secretion is the movement of waste in the ______ back into the tubule via ______ transport. What are some examples?
Secretion is the movement of waste in the blood back into the tubule via active transport. Ex. urea, vitamin C, drugs, H+
During secretion, urine is collected into the ________ duct and via the renal _______ passes into the _______.
collecting duct, pelvis, bladder
Why can blood cells and proteins not be filtered?
Too big to pass capillary wall
where is the highest concentration of Na+ found?
bottom of the loop of Henle
The kidney has the ability to restore the pH only if it is too ____? (high/low). This means there are too many ____ ions.
Low, H+
the nephron will do two things to lower pH
- reabsorb _____ (binds to H+) and lowers H+ in blood
- secrete H+ (blood to tubule to be excreted as ______)
HCO3-, urine
When the _________ detects increased solute in the blood, it gives posterior pituitary a signal to release ____ into the ________.
When the hypothalamus detects increased solute in the blood, it gives posterior pituitary a signal to release ADH into the blood.
What does ADH stand for? What does it do?
Ant-diruetic hormone. Causes kidneys to release water (reabsorb water)
ADH targets the ________ duct of a nephron by decreasing _____ excretion. (note: water is not in nephron, it is in the blood)
collecting duct, urine
Eventually, when there is too much water in the blood there it too low _____. __________ detects this and tells posterior pituitary to stop releasing ______.
solute, hypothalamus, ADH
If alcoholic drinks inhibit ADH, what is there main symptom?
pee more, thus more dehydrated
Which kind of diabetes produces not enough ADH? What is the main symptom?
Peeing a lot, feeling thirsty
The stimulus for the kidney and blood pressure relationship is ______ blood pressure due to ______ blood volume.
low, low
What specialized group of cells first detects low blood pressure? Which arteriole are they found in?
JGA (juxtaglomerular apparatus), found in afferent arteriole
JGA converts in inactive protein angiotensinogen into ________.
This targets the adrenal gland, which produces the hormone ________.
This hormone causes more _____ to be reabsorbed into the blood. Since water follows _______, water volume increases.
More water = more _______.
JGA converts in inactive protein angiotensinogen into angiotensin.
This targets the adrenal gland, which produces the hormone aldosterone.
This hormone causes more Na+ to be reabsorbed into the blood. Since water follows solute, water volume increases.
More water = more pressure.
What are hormones?
Chemical secreted into blood by cells of the endocrine system
Endocrine glands are ______ the body. What are 3 examples?
inside
examples: adrenal, pituitary, thyroid
What are the two main differences between protein hormones and steroid hormones? (note: solubility and ability to pass membrane)
- protein hormones: water soluble, bind to cell membrane receptors
- steroid hormones: non-water soluble, pass through the plasma membrane and attach to receptors inside the cell
The hypothalamus produces __________ cells in both the posterior and anterior pituitary glands. But in which side do the cells contain a releasing hormone?
neurosecretory, anterior pituitary neurosecretory cells have releasing hormones
Hormones are produced by the ________ and carried directly to the _________ pituitary and released into the blood.
hypothalamus, posterior
neurosecretory release ________ hormones into the blood. The blood carries them to the ______ lobe of the pituitary to secrete its hormones.
releasing, anterior lobe
which two hormones are stored in the posterior pituitary?
oxytocin and ADH
In the long-term stress response, the hypothalamus secretes a ________ hormone (ACRH).
BONUS: what does it stand for?
releasing
Adrenocorticotropin Releasing Hormone
ACRH causes which lobe of the pituitary to release ACTH?
BONUS: what does ACTH stand for?
The anterior lobe.
ACTH stands for anteriorcorticotropin hormone
ACTH is carried by blood to the ______ cortex where is secretes which two corticoids?
adrenal cortex
- glucocorticoids
- mineralocorticoids
Mineralocortocids increase the amount of _____ ions in the kidney. This causes _____ to follow and therefore increased ______ pressure.
Na+, water, blood pressure
Glucocorticoids cause proteins and fats to be ______ down and converted into ______. This _______ system is also suppressed, making one more likely to develop a _____.
Glucocorticoids cause proteins and fats to be broken down and converted into glucose. This immune system is also suppressed, making one more likely to develop a cold.
During the short-term stress response, cells in the hypothalamus send signals to _______ cells in the ______ cord.
Cells in the ______ cord stimulate adrenal _______ to secrete _________.
During the short-term stress response, cells in the hypothalamus send signals to nerve cells in the spinal cord.
Cells in the spinal cord stimulate adrenal medulla to secrete epinephrine.
Epinephrine causes increased _______. Glycogen to be converted into ______ for the body to use. There are also changes in ______ flow pattern to increase circulation.
Epinephrine causes increased metabolism. Glycogen to be converted into glucose for the body to use. There are also changes in blood flow pattern to increase circulation.
Most of the pancreas is an _______ gland. 2% of the cells in the pancreas are specialized _______ cells that form clusters called the _____ of ________.
Most of the pancreas is an exocrine gland. 2% of the cells in the pancreas are specialized cells that form clusters called the islets of Langerhans.
The islets of langerhan contain alpha and beta cells. Alpha cells produce _______ and beta cells produce ______.
alpha: glucagon
beta: insulin
What event would cause beta cells to produce insulin?
A rise in blood glucose after a meal
Insulin instructs the body to _____ its blood glucose levels.
It targets _____ body cells and tells them to take up glucose.
lower, all
What does insulin inhibit in the liver?
The breakdown of glycogen into glucose
Insulin promotes _____ tissue to uptake glucose while ________ the breakdown of fats into _____ acids.
Insulin promotes fat tissue to uptake glucose while preventing the breakdown of fats into fatty acids.
Glucagon produced by _____ cells have an _________ effect from insulin. This means opposite.
alpha, antagonistic
Glucagon _______ blood sugar levels by stimulating the breakdown of _______ into glucose.
raises, glycogen
Glucagon also stimulates the breakdown of fats into _____ ______ and proteins into _____ _______.
fatty acids, amino acids
A cells ability to use amino acids and non_______ helps maintain blood glucose while ________.
carbohydrates, fasting
When blood glucose is too high, beta cells turn up _______ production, and alpha cells inhibit _______ production
insulin, glucagon
When blood glucose levels are low, alpha cells turn up _______ production, and beta cells inhibit _______ production.
glucagon, insulin
Diabetes insipidous is a condition in which not enough _____ is produced. What is the body not able to do?
The body is not able to reabsorb enough water into the blood. This results in a constant need to pee
Diabetes mellitus is characterized by a ______ blood glucose level. What are the 3 classic symptoms?
high
- frequent urination
- increased thirst
- increased apetite
If untreated, what are 3 long-term effects of diabetes?
- loss of vision
- kidney failure
- cardiovascular problems
What is the difference in issues between Type 1 and Type 2 diabetes? Difference in treatment?
1: beta cells do not produce insulin, daily insulin shots
2. insulin receptors do not function properly, balanced diet
What is the difference onset between Type 1 and Type 2 diabetes?
type 1: usually infancy
2: adulthood
Type 2 is strongly associated with ________. There has also been found to be an 80% ______ linkage.
obesity, genetic
Gestational diabetes is a high blood ______ level in ________ woman.
glucose, pregnant
If calcium levels in the blood rise past their set point, the thyroid releases the hormone ________.
calcitonin
Calcitonin targets the ______ which will take up _______ and other mineral deposits. Calcitonin also targets the _______ which reduce calcium reabsorption into the blood (more in ______).
Calcitonin targets the bones which will take up calcium and other mineral deposits. Calcitonin also targets the nephrons which reduce calcium reabsorption into the blood (more in urine).
When blood calcium decreases below the setpoint, the _________ gland releases _____.
parathyroid, PTH
Mammals have ____ parathyroid glands, each about the size of a ____
4, a pea
PTH targets which three areas of the body?
- Bones: increased calcium
- Kidneys: increased calcium
- Small intestine: more calcium in blood than in feces
calcium is essential for which two things? what can a deficiency cause? overproduction?
- blood clotting, muscle contractions
- not enough: twitching muscles and cramps
- too much: weak muscles, osteoporosis
What are the two main phases of the menstrual/ovarian cycle?
follicular phase and luteal phase
During the follicular phase…
- The hypothalamus releases _______.
- This goes to the anterior pituitary which releases _____ and _____. These two hormones target the ______.
- FSH causes several oocytes to start developing into ______ cells.
- Only ___ develops to maturity.
- The hypothalamus releases GnRH.
- This goes to the anterior pituitary which releases LH and FSH. These two hormones target the ovary.
- FSH causes several oocytes to start developing into follicle cells.
- Only 1 develops to maturity.
The growing ______ under the influence of FSH and LH produce _______.
follicle, estrogen
At low {estrogen}, there is negative feedback on _____.
At high {estrogen}, there is positive feedback on _____ (day ___) to the hypothalamus to release more ______.
At low {estrogen}, there is negative feedback on FSH.
At high {estrogen}, there is positive feedback on LH (day 12) to the hypothalamus to release more GnRH.
When a follicle ruptures, an ____ is released and lots of _____ is secreted. This process is called ______.
When a follicle ruptures, an egg is released and lots of LH is secreted. This process is called ovulation.
LH causes a ruptured follicle to create the ________ _______.
corpus luteum
The buildup of the corpus luteum produces which 3 hormones in excess?
Which two hormones are inhibited?
progesterone, estrogen, inhibin
what does the corpus luteum do?
the corpus luteum prepares the uterus to receive a fertilized egg
increased levels of progesterone cause _______ feedback to the hypothalamus. this shuts down GnRH and therefore which other two hormones?
negative feedback, FSH and LH
Which hormone mainly promotes the thickening of the uterine lining?
progesterone
Inhibin specifically inhibits the release of _____ from the pituitary. This prevents the start of _____ development at around day ____.
Inhibin specifically inhibits the release of FSH from the pituitary. This prevents the start of follicle development at around day 14.
If fertilization does not occur, the ______ _______ degenerates and levels of _________, ________, and _______ decrease. Which two hormones are no longer inhibited?
If fertilization does not occur, the corpus luteum degenerates and levels of estrogen, progesterone, and inhibin decrease. FSH and LH are no longer inhibited.
why does one bleed on their period?
uterine lining is shed (endometrium)
if fertilization of an egg does occur, where is it implanted? Which hormone known as the pregnancy hormone, is released?
implanted in the uterine lining. HCG is known as the pregnancy hormone (Human Chronic Gonadotropin)
what is the main function of HCG?
prevent the degeneration of the corpus luteum
after 10, weeks, what takes over the function of the corpus luteum?
the placenta
LH targets _______ cells and tells them to release the hormone _________.
Leydig, Testosterone
FSH targets _______ cells. It helps a binding protein bind w _________ to stimulate ______ production.
FSH targets sertolli cells. It helps a binding protein bind w testosterone to stimulate sperm production.
Where do sperm develop and mature?
seminiferous tubules
the negative feedback system is males….
When __________ is overabundant, it tells the hypothalamus to stop producing GnRH. _______ cells are also stimulated and told to secrete inhibin needed to stop _____ production.
When testosterone is overabundant, it tells the hypothalamus to stop producing GnRH. Sertolli cells are also stimulated and told to secrete inhibin needed to stop FSH production.
Where are mature sperm stored?
epididymus
