topic.4.Homeostasis.powerpoint4.0.homeostasis-overview Flashcards
what does “-stasis” mean?
restore balance
T/F homeostasis is static
False, it is dynamic
Homeostasis
Internal responses that compensate for changes in the environment
Internal responses are __
physiological processes that your body enacts in order to maintain proper and maximum efficient functioning of the body
What is extracellular fluid?
interstitial fluid and plasma
plasma
liquid component of blood
What is interstitial fluid?
Interstitial fluid is the fluid that fills in the space between cells. It contains ions and complex molecules
-involved in removal of waste
Homeostasis mechanism maintains what 4 things *
-concentration of oxygen and carbon dioxide
-pH of internal environment
-concentration of nutrients/waste/salts/electrolytes
-volume and pressure of extracellular fluid
what are the two major control systems of homeostasis and why
nervous and endocrine- they regulate the others
name the 11 organ systems
nervous
endocrine
muscular
skeletal
integumentary
circulatory
lymphatic/ immune
respiratory
digestive
excretory
reproductive
What are 4 receptors that help maintain homeostasis?
1) chemoreceptors: Gas composition and pH balance
2) baroreceptors: Maintain blood pressure
3) osmoreceptors: water balance
4) thermoreceptors: temperature regulation
aN INTRINSIC CONTROL CAN CAUSE..
Cause dilation of blood VESSELS
Ex:
HELPS RETAIN HOMEOSTASIS
What is the intrinsic control that occurs when you exercise?
Background: When you exercise, your muscle uses more oxygen
Intrinsic control: vasodilation
1) Nerves in the walls of blood vessels release acetylcholine
2) Acetylcholine binds to chemoreceptors on endothelia cell
3) Activates NOS(Nitric oxide synthase), that converts arginine into NO
4) NO binds to guanylyl cyclase on smooth muscle cells, relaxing it by opening up the lumen of blood vessel
5) resulting in dilation of blood vessels.
Active hyperemia is what?
Increased blood flow to tissue involved in metabolic activity
endothelial cells are derived from _
mesoderm
epithelia cells are derived from_
endoderm
Blood vessels are usually lined by _ cells
endothelial cells which are derived from mesoderm
What is the primary mechanism of homeostasis?
Negative feedback
Name the 5 parts of negative feedback and what they do
- stimulus- the change that happens
- sensory receptors-cells detect
stimulus - integrator- brain or whatever processes info
- effector- muscle or gland that elicits a response
- response- system output signals (counteracts stimuli)
What are the three ways our body transmit signals?
-endocrine signaling(hormones)
-sensory transduction(action potential transmission)
-signal transduction(molecular/cellular level)
Sensory transduction involves _ that is converted to _
stimulus, action potential
Explain how our retina is an example of sensory transduction
Sensory cells in the retina detect stimulus(light) and is converted into electrical impulses(action potential) that are
transmitted along axons to the central nervous system
what is the difference between endocrine signaling and signal transduction
endocrine-> long distances in the body (blood stream)
signal transduction-> from cell to surrounding cells
where do baroreceptors send signals to?
brainstem
What are baroreceptors?
Neurons involved in the heart, are sensitive to changes in blood pressure. They do so by detecting electrical impulses caused by the stretching of blood vessels. they relay action potential(AP) to the brainstem.
what is postural hypotension?
bp falls when you stand up causing baroreceptors to decrease in their firing
How is homeostasis restored in postural hypotension?
Baroreceptors strectched less and the rate of AP to the brainstem decreases which increase cardiac output and blood pressure rises
where do chemoreceptors send their info to?
brainstem. some of them are even located there
where do osmoreceptors send their information to?
hypothalamus
Differentiate b/w hypertonic, isotonic, hypotonic
isotonic: outside=inside
hypertonic: outside > inside, water moves out of cell causing shrinking aka crenation
hypotonic: inside> outside, water move into cell and cell gets swollen
Explain the signal pathway that causes you to get thirsty.
- osmoreceptors in the hypothalamus detects increase in solvent concentration in ECF aka dehydration
- The hypothalamus stimulates thirst
Explain the signal pathway caused by dehydration. (involves ADH)
1.the hypothalamus stimulates the posterior pituitary to releases antidiuretic hormone(ADH)
2.ADH makes the kidney reabsorb water, reducing urinary output
(makes the distal convoluted tubules permeable to water)
Osmoreceptors detect changes in _
osmotic pressure;
the minimum pressure that must be applied to a solution to halt the flow of solvent molecules through a semipermeable membrane
Distal convoluted tubule
portion of kidney nephron
The bicarbonate buffering reaction regulates?
PH homeostasis, maintaining blood pH between 7.35-7.45
What is the what is the pH buffering equation?
CO2 + H2O <->H2CO3(carbonic acid)
<->HCO3-(bicarbonate) + H+
Acidosis is related to _
pH buffering equation
What are the three kinds of acidosis discussed in this class?
Respiratory acidosis
Keto acidosis
Metabolic acidosis
Respiratory acidosis
decreased respiration causes increased blood carbon dioxide, pH buffering equation shows the rise of CO2 results in the rise of H+ making PH more acidic and decreasing PH
An example of respiratory acidosis is
COPD: Chronic obstructive pulmonary disease-poor airflow as a
result of breakdown of lung tissue or irritation of the trachea and
bronchioles leading to inflammation (smoking)
metabolic acidosis
Can occur if the nephrons in kidneys are not removing enough acid (H+)from the body.
what is a nephron
the functional unit of a kidney
What might cause metabolic acidosis?
kidney failure
keto acidosis
Body fails to adequately regulate ketones;
accumulation of keto acids decreases blood pH
Ketones are
bi-products of fatty acid breakdown, eg. acetone, acetoacetic acid
What are two examples of keto acidosis?
Diabetics (type 1): lack of insulin, no glucose absorption, so the body switches to fatty acid metabolism, get ketones
Alcoholic ketoacidosis
alcohol blocks the first step of gluconeogenesis, the body doesn’t synthesize enough glucose, fatty acid metabolism, get ketones
-Accumulation of keto acids decreases blood pH
Accumulation of keto acids___
decrease blood pH
what is gluconeogenesis?
metabolic pathway that results in the generation of glucose from non-carbohydrate carbon substrates such as lactate, glycerol, and glucogenic amino acids.
How does hyperventilation restore pH homeostasis?
Alkalosis
Release of CO2(breathing), shifts pH buffering equation to the right, meaning more H+ is being used, raising pH if it was too acidic beforehand
When you hyperventilate, why do people say to breath into a bag?
hyperventilate you lose lots of CO2, by breathing into bag you inhale CO2 back to help restore levels
