PhysioEx Practical 1 - BSC2086L

What is the resting membrane potential of a neuron caused by?

Na+ and K+

What alters the resting membrane potential?

Alterations to the ion concentration inside or outside the neuron

Why is there a greater resting membranepotential when the extracellular [K+] was increased compared to a similar decrease in extracellular

more passive K+ than passive Na+

What does decreasing extracellular Na+ concentration do to membrane potential

more negative

what does increasing extracellular K+ do to membrane potential

less negative

what happens when correct stimulus is applied

receptor will open or close membrane ion channels

Pacinian corpuscles respond to high to low amounts of ______.
Unresponsive to ____, _____, or _____

pressure
chemical, heat, light

Olfactory receptors respond to low to high amounts of _____ _____.
Unresponsive to _____, ______, ______.

chemical stimuli
heat, pressure, light

What do free nerve endings respond to?

heat, pressure

What needs to happen in order to generate action potential?

change in voltage

What does the membrane potential have to reach before action potential can be generated

threshold

What stimulus voltage causes action potential in the nerve?

20 and above

Why was there no decrease in magnitude of action potential

action potential is regenerated at each segment of axon

What happens during action potential propagation

an influx of Na+ into the axon triggers the depolarization of adjacent axon segments

What happens when axon segment is in refractory period

it cannot respond when it is depolarized to threshold

TTX is a sodium ____

antagonist

What happens when threshold voltage is reached

the activation gate opens, allowing Na + to enter the cell

What is it called when depolarization of the membrane does not elicit another action potential

refractory period

What is it called when an action potential can be generated as it required a greater depolarization than usual to reach threshold state

relative refractive period

Why does increasing voltage not have an effect on the nerve

you are within the absolute refractory period of the nerve

once an action potential is generated, it always has the same _____

magnitude

_____ of the action potential is not the same for all axons

speed

What can affect the speed of the action potential

myelinated axons, larger diameter axons

Which fibers have tje fastest action potential conduction speed?

Type A

Which fibers have small diameters and no myelination and therefore have the lowest action potential conduction speed

Type C

Which fibers have a medium diameter axons that have some myelination so they will have action potential conduction speeds that are in between the other fibers

Type B

What happens when action potential reaches axon terminal

voltage gated Ca2+ channels open

What happens if the extracellular fluid contains no Ca2+

neurotransmitters will not be released since exocytosis will not occur

What happens if extracellular concentration of Ca2+ is low?

will reduce the amount of neurotransmitter released since less exocytosis will occur

What happens if Mg2+ is added to extracellular fluid?

Mg 2+ will act as a calcium channel blocker.

What is propylthiouracil?
What does it do?

antithyroid medicine, inhibits the production of thyroxine;
makes it harder for the body to use iodine to make thyroid hormone

what is the experiment trying to prove?

...

What is the purpose of TSH? Thyroxine?

TSH - tests how much of the hormone is in your blood and how well your thyroid is working
Thyroxine - controls how much energy your body is using

Whose metabolic rate was the highest?

normal rat

Why can't Tx rate produce thyroxine to increase metabolism

lacks a thyroid gland

Why can't hypox rat produce thyroxine

lacks pituitary gland

What happens with removal of pituitary gland?

all hormones are removed with the gland

What happens if thyroxine is injected in any of the rats?

an increase in metabolism compared to their base metabolic rat

What compensates for the lack of thyroid gland

thyroxine

What happens if TSH is injected to the normal and hypox rats

increase in metabolic rate compared to the baseline

Why doesn't metabolic rate increase for Tx rat after TSH injection

lacks thyroid gland for TSH to stimulate

normal rat - NA
Tx rat - lacks ____ gland
Hypox rat - lacks _____ gland

thyroid
pituitary

Why does TSH injection increase metabolic rate in hypox rat even though it lacks pituitary gland?

simulates the actions of a pituitary gland to cause thyroxine release from the thyroid gland which increases metabolism.

What is followed by the secretion of TRH in normal rat

increase in TSH secretion

Why doesn't TSH injection increase metabolic rate for Tx rat

lacks thyroid gland

What happens to metabolic rate in normal rat after injection of propylthiouracil? tx and hypox rat<

decreases;
no effect

Why is production of functional thyroid hormone prevented and it mimics a diet low in iodine

propylthiouracil (PTU) blocks the attachment of iodine to tyrosine

How to determine the unknown amount of glucose in a sample?

glucose standard graph

Since the optical density _______ proportionally as the amount of glucose ______, a straight line can be drawn from the optical density values.

increases; increases;

Where can blood be drawn from since there isn't a significant difference in the plasma glucose of blood in those locations?

finger or arm

What is the fasting plasma glucose of a normal person

less than 110 mg/dl

What FPG value indicates impairment of borderline impairment of insulin-mediated glucose uptake

between 110 and 126 mg/dl

What FPG value to be diagnosed with diabetes?

above 126

What diabetes occurs during pregnancy?

gestational

What is a T score

measurement of the mineral content of bone

Normal T score range-
Osteopenia-
Osteoporosis-

1 to -0.99
-1.0 to -2.49
-2.5 and below

what were ovariectomized rats used for in this experiment

stimulate menopause when the ovaries would stop producing estrogen

HRT with estrogen _______ the strength of the bone tissue and improved the rat's condition to osteopenia.

increased

What are the risks of HRT even though it increases bone density

increase risk of uterine/breast cancer, blood clots, and strokes

Corticotropin-releasing hormone (CRH)

stimulates the anterior pituitary gland to release adrenocorticotropic hormone (ACTH).

ACTH

stimulates the release of cortisol from the adrenal cortex

As cortisol levels rise, what can it inhibit?

the release ofCRH (from the hypothalamus) and ACTH (from the anterior pituitary)

Cushing's Syndrome

Increased blood levels of cortisol (hypercortisolism) caused by an adrenal gland tumor

Cushing's disease

hypercortisolism caused by an anterior pituitary tumor

What is the difference between Cushing's syndrome and disease?

syndrome - primary hypercortisolism caused by an adrenal gland tumor
disease - secondary hypercortisolism caused by a pituitary tumor

Addison's disease

Hypocortisolism because of destruction of the adrenal cortex

What happens in hypopituitarism

damage to the anterior pituitary causes secondary adrenal insufficiency

physioex4 activity 1 results

physioex4 activity 2 results

physioex4 activity 3 results

physioex4 activity 4 results

physioex11 activity 1 results

hematocrit

the height of the red blood cell layer divided by the total height of blood (packed cell volume divided by total blood volume)

Where are the heavier items (RBCs) in blood packed after cetrifugation?

the bottom

buffy coat

what is the layer of white blood cells above the RBCs called?

plasma

what is the liquid component above the buffy coat called?

erythropoietin (EPO)

what is RBC production stimulated by?

kidneys

what is EPO released from

low O2 content of blood or the sex hormone testosterone

what is EPO release triggered by

42-52% males
37-47% females

average hematocrit for males and females

Why is hematocrit higher in males?

more testosterone

What happens to RBC production at higher altitudes?

production increases

what does anemia cause

a reduction in erythrocyte population which reduces the hematocrit and oxygen transport in blood

physioex11 activity 2 results

settling of RBCs is a _____ process in a normal person

slow

what does increased production of fibrinogen and immunoglobulin cause RBCs to do

clump together and/or stack up (rouleaux formation), making them heavier and settle faster

normal ESR

5 mm/hr

what diseases cause an increase in ESR

iron-deficiency anemia, myocardial infarction (heart attack), and acute pelvic inflammatory disease

Sickle Cell anemia vs iron deficiency

iron deficiency anemia shows an increased ESR, sickle cell anemia shows a lower ESR

why doesn't angina pectoris have no effect on the ESR

angina pectoris is not necessarily associated with a myocardial infarction

what does sickle cell anemia prevent

normal sedimentation

who has a higher sedimentation rate

menstruating females and people with iron deficiency

physioex11 activity 3 results

normal blood avg

12-18 g/100 ml

normal ratio of packed cell volume to hemoglobin

3:1

People live at higher altitudes, suffering from polycythemia, suffering from congestive heart failure, or suffering from chronic obstructive pulmonary disease (COPD) will have _______ Hb levels

higher

People suffering from anemia, hyper thyroidism, cirrhosis of the liver, renal disease, systemic lupus erythematosus, and severe hemorrhage (blood loss) will show a _______ in hemoglobin levels

decrease

physioex11 activity 4 results

what does red bone marrow produce

RBCs

how to determine blood type

specific cell surface antigens on the plasma membrane of red blood cells