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Biology > Homeostasis > Flashcards

Homeostasis Flashcards

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1
Q

What is the internal environment

A

Composed of extracellular fluid which has interstitial fluid and plasma
-NOT intracellular fluid

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2
Q

In order to survive all organisms must

A
  1. take in nutrients, process, and dispose them
  2. they must respond to change in environment
  3. produce molecules like fat, carbs, proteins, for cellular function
  4. protect body from injury and fight infection
  5. reproduce
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3
Q

Most important systems for maintaining homeostasis

A

Nervous and endocrine

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4
Q

Monitor organ systems

A

organ systems that send signals when body’s organ function goes out of normal range

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5
Q

Negative feedback

A

Primary mechanism of homeostasis, cancels/counteracts the stimulus

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6
Q

Explain the pathway of homeostatic mechanism

A

Stimulus -> sensory/receptor -> sensory pathway -> afferent neurons -> integrator/CNS/interneurons -> motor pathway/efferent neurons -> effectors

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7
Q

What is the set point

A

Optimal value of a system, if it goes beyond this value your integrators activates effectors

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8
Q

What happens when the body is cold

A

Stimulus: being cold
Thermoreceptors detect the temperature change
Send through the sensory pathway through afferent neurons
Send to the CNS with interneurons which process info
Send to the efferent/motor pathway
Efferent neurons send signals to your effectors

Effector response:

Your blood vessels will constrict so thermal energy isn’t lost
You will also shiver which generates body heat

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9
Q

What happens when the body is hot

A

Stimulus: increase in temperature
Thermoreceptors detect increase in temperature and then send to afferent neurons in your sensory pathway to the interneurons in the central nervous system.
Central nervous system processes information, compares to a set point and then sends out signal
Signal is sent through efferent neurons in motor pathway

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10
Q

What happens when theres a fever in your body?

A

Your body’s set point increases in response to the virus to fight off the infection and return to normal

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11
Q

Positive feedback + examples

A

An increase in the environmental stimulus
Does not maintain homeostasis
-flight or fight
-childbirth (releases oxytocin which stimulates contractions)

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12
Q

What kind of receptors detect temperature change?

A

Thermoreceptors in your skin and organs which compare to your set point

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13
Q

Explain flight or fight and oxytocin as positive feedback

A

When you get scared, your body releases hormone epinephrine and norephrine which increases when more is secreted
Oxytocin is secreted in response to childbirth

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14
Q

Which part of the brain controls temperature?

A

The hypothalamus

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15
Q

What is osmoregulation

A

The regulation of osmotic pressure which is the difference in water/solute concentration across a membrane

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16
Q

What are nephrons

A

The functional unit of the excretory system that regulate water balance and urine output

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17
Q

What kind of animals are able to secrete ammonia?

A

Animals that have high levels of water inside of their body like freshwater fish are able to dilute the ammonia and keep it safely in their bodies

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18
Q

Blood flow in kidneys

A

Renal artery > afferent arteriole > glomerlus > efferent arteriole > pertibular capillaries > renal vein

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19
Q

Fluid flow in the kidneys

A

Bowman’s capsule > proximal convulated tubule > descending loop of henle > ascending loop of henle > distal convulated tubule > collecting ducts > renal pelvis > ureter > urinary bladder > urethra

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20
Q

Explain the whole entire process of filtration

A
  1. Blood flows in from the renal artery into the afferent arteriole into the glomerulus and filters out glucose, ions, urea, a.a, small nutrients
    keeps the large proteins, blood cells, and platelets

The fluid that is filtered into the glomerulus is called the filtrate

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21
Q

Explain the process of reabsoprtion

A

The point of reabsorption is to reabsorb most nutrients as well as water into the extracellular fluid

1.Active transport pumps pump out Na+ K+ and Cl- as well as a.a, glucose, from the filtrate and then since the solute concentration is so high outside water flows out and follows it (passive)

Remaining nutrients and water are reabsorbed by proximal convoluted tubule and taken into the peritubular capillaries to send back to blood

  1. Then the remaining fluid flow into the descending loop of henle where most water is reabsorbed and becomes very hyperosmotic (due to high solute)
  2. Goes up the ascending loop of henle where more ions are reabsorbed and its passive at first due to the high solute concentration but active as it heads up
  3. Distal convulated tubule- Then remaning solutes like Na+ Cl- HCO3- are moved out making it hypoisomotic and then water follows it out
  4. In the collecting ducts, urea and waste enter through the ducts and its permeable to water but not salt ions therefore the urine becomes very concentrated
  5. Goes out through the renal pelvis for excretion
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22
Q

Secretion

A

Secretion is secreted waste into the nephron to remove it
-occurs in the convoluted tubules and collecting ducts
-primarily hydrogen ions are secreted back into the nephron to control acidity

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23
Q

What happens when the aciditiy of interstitial fluid gets too high?

A

H+ ions are secreted into the nephrons and they are released in urine to control pH

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24
Q

A patient did not 100% reabsorb their glucose, and their urine was detected with high levels of sugar. Why is this?

A

This person is diabetic, they do not have insulin to lower their levels of glucose therefore they have high levels of glucose in their blood and not all of it can be reabsorbed back

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25
Why are there high levels of urine in a diabetic person?
They have a lot of solute in their filtrate which means theres less water so water is going to move in to restore that balance and its gonna cause more urine.
26
What is ADH what does it do?
Antidieuretic hormone is released by the posterior pituriary and causes kidneys to increase their water reabsorption - the hypothalamus detects high solute concentration in the blood and sends a signal to the posterior pituitary to drive water out of filtrate -when ADH reaches the kidneys the convoluted tubules and the collecting ducts to become more permeable to water and returns water to blood
27
Aldosterone
A hormone released when blood pressure is low (which means theres low water), and increases Na+ reabsoption -when Na+ is reabsorbed, water follows it out and blood pressure increases
28
What happens when you sweat? What happens to urine output?
When you sweat you lose water in your interstitial fluid, which means that theres going to be higher solute concentration in the blood. This is going to make more water flow out of the nephrons in order to balance water so urine output will decrease.
29
Protein hormones
-made from amino acids -they are hydrophilic -bind to receptors on the membrane and signal a cascade of reactions -
30
Steroid hormone
-made from cholesterol -they diffuse through the membrane and attach to receptors inside of the cell -the receptor-hormone complex then attaches onto a segment of gene
31
What kinds of hormones does the hypothalamus release?
Stimulating/inhibting hormones
32
What is the hypothalamus controlled by
Other inputs from neurons from the nervous system, your neurons take the signal that your body needs something and sends it to the hypothalamus
33
What is the master gland
The pituitary gland
34
Growth Hormone
Stimulates protein synthesis, bone growth in children, cell division -works with insulin like growth factor -maintain blood and glucose levels between meals
35
Thyroid releasing hormone
Stimulates TSH in the anterior pituitary to release
36
Thyroid stimulating hormone
Stimulates production of calcitonin and thyroxine
37
Adrenocorticotropic release hormone (ACTH)
Stimulates the release of cortisol in the adrenal cortex
38
Follcile stimulating hormone
Stimualtes the release of eggs and folliciles in female and spermatogensis in male
39
Lutenizing hormone
Controls the male sex hormone and regulates menstrual cycle in females
40
What two hormones do thyroid release
Calcitonin and thyroxine
41
Why is iodine so important in the diet?
Iodine is important because it is need to produce thyroxine and thyroxine sends negative feedback to the pituitary so if there's not enough thyroxine, it's going to form a goiter due to inability to send negative feedback
42
What hormones do parathyroid glands produce?
Parathyroid hormone which also releases calcitriol
43
Calcitriol
hormone released by the parathyroid hormone and is active form of vitamin D, it increases absorption of Ca2+ from food
44
Thyroxine
Thyroid hormone released by the thyroid glands which assist in metabolism, development, maturation and interacts with growth hormone
45
Calitnonin
Released by the thyroid and lowers Ca2+ levels in blood
46
Parathyroid hormone
Increases Ca2+ levels in blood by taking calcium out of bones - can cause osteoporosis
47
Adrenal medulla secretes
Secretes epinephrine and norephrine
48
What is epinephrine and norephrine function
They increase heart rate, prepare body for stress, dialate airways, increases breakdown of glucose and fats for fuel
49
Adrenal cortex secretes ____ which...
Secretes cortisol which increases blood glucose levels and decreases glucose uptake by body cells promotes breakdown of fatty acids and proteins
50
Two hormones that control blood sugar
Insulin and glucagon, released by pancreas by islets of langerhams Insulin - beta ceclls Glucagon - alpha cells
51
What does insulin do
-lowers blood sugar glucose -> glycogen fatty acids -> fats amino acids -> proteins
52
What does glucagon do
-increases blood sugar -usually in response to fasting glycogen -> glucose fats -> fatty acids proteins -> a.a
53
Diabetes Melitus
A person who cannot produce insulin and has consistenly high blood glucose levels -damaged tissue -frequent urination -thirsty -increased appetite
54
What is GnRH
the neurohormone that stimulates LH and FSH
55
What does LH stimulat
male sex hormones and female menstrual cycle hormones
56
What does FSH stimulate
stimulates egg and sperm production
57
Explain the pathway of GnRH in males
GnRH -> LH and FSH from anterior pituitary gland LH stimulates leydig cells in testes to produce testosterone FSH stimulates sertoli cells in testes to begin spermatogensis When testosterone levels are high... it inhibits GnRH and also releases inhibin which inhibits FSH
58
Explain the pathway of GnRH in females
GnRH -> LH and FSH from anterior pituitary FSH -> creates growing follicile -> follicile releases estrogen LH -> stimulates growth of the corpus luteum > corpus leteum rleeases progesterone and some estrogen
59
What does estrogen do
Stimulates development of secondary sexual characteristics
60
What does progesterone do
Stimulates development of uteral lining, inhibits cramps and inhibits GnRH which inhbits LH and FSH also releases inhibin
61
Explain the menstrual cycle
GnRN -> LH and FSH FSH creates the follicile and egg and the follicile releases estrogen The estrogen in small amounts inhibits FSH and stimulates LH (which produces some estrogen) The sudden peak in LH stimulates the formation of corpus leutum which releases progesterone and also releasing of the egg Progesterone stimulates uteral lining, inhibits cramps, inhibits the GnRH and also releases inhibin -fertilization does not occur then the corpus leteum breaks down and then uterus is shed and repeat cycle
62
Neuron
specialized nerve cell that carries electrical signals
63
Afferent neurons
Take stimuli from receptors and send it to the interneurons in CNS
64
Explain the whole subdivision of the nervous system
Draw out the chart
65
Somatic vs automic
somatic = voluntary -> skeletal muscles, shivers autonomic = involuntary
66
Sympathetic vs parasympathetic
Sympathetic - flight or fight Parasympathetic - rest relax both affect smooth muscles and glands
67
Explain examples of parasympathetic vs sympathetic
parasympathetic = -constrict pupils, salivation, heart rate lowers, relax airways, digestive activity, stimulates gallbladder -contracts bladder -relaxes rectum sympathetic -dilates pupils, inhibits salivation, increases heart rate, stimulates glucose release, secretion of norephrine by adrenal medulla
68
What is a reflex arc
A neural circuit that does not require coordination from the brain but uses the spinal chord instead
69
Synapse
site where two neurons make connections or a neuron with an effector
70
Axon terminal side is the ________ dendrite side is the _________-
Axon terminal - the presynaptic cell dendrite - post synaptic cell
71
Conduction across a chemical synapse explain
normally Ca2+ channel proteins actively shuttle Ca2+ out of the axon to keep the concentration high outside and low inside Action potentials travel along an axon and then once it reaches the axon terminals, and this causes Ca2+ gates in axon terminal to open Ca2+ channels (passive) and bring them into the cytosol The rise in Ca2+ triggers a protein to release which makes vesicles fuse with the plasma membrane This release neurotransmitters into the synaptic cleft by exocytosis Neurotransmitter molecules diffuse across the cleft and bind to the receptor molecules in the membrane of the postsynaptic neuron The binding of these neurotransmitters opens ion channels which allows ions to flow into dendrite/cell body of postsynaptic neuron If the post synaptic neuron becomes depolarized by the ions moving in to the point of threshold, it generates another action potential
72
What is the charge of teh axon at resting potential?
negative inside + outside Na/K pump 3 Na out 2 K in
73
What voltage is resting potential
-70mV
74
Explain an action potential
Stimulus occurs: spider on hand Phase 1: the stimulus brings incoming + ions and raises the membrane potential until it reaches the threshold potential and then depolarizes Phase 2: Above the threshold potential, Na+ channels continue to open and positive ions flow into the axon and then it reaches a maximum peak Phase 3: The action potential reaches it peak at around 30mV and here sodium channels close and K+ channels reopen Phase 4: The K+ ions flow out of the ion and keep flowing out and repolarizes the axon Phase 5: The axon briefly hyperpolarizes because k+ channels are slow to close Phase 6: Membrane potential stabilizes at resting value and ready for a new action potnetial Phase 4:
75
All or nothing principle
Once the stimulus passes the threshold potential it will generate an action potential no matter the strength of stimulus
76
Refractory period
Begins at the peak of the action potential and makes it hard for another action potetial to be generated until the current one has restabilized at resting potnetial -ensures one way movement
77
Why do myelinated axons increases the speed of electrical impulses?
They insulate parts of the axon and the nodes of ranvier are very concentrated in ion channels so they can jump really fast
78
Electrical synapse
Electrical currents travel across and travel through gap junctions
79
Chemical vs electrical synapse
Chemical is slower, but more precise and selective Electrical is faster but its a lot harder to control since the electric currents activate consecutively

Biology (8 decks)

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