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