Lab Midterm - Physiology

what are methods of dispersion

standard deviation

standard error

variance

what is a t-test?

a statistical test used to compare the

means of two populations or distributions

If P > 0.05 then…

there is no statistical

difference between the populations

If P<0.05…

the populations are considered statistically different

t value > CV…

reject null hypothesis

t value < CV…

fail to reject null hypothesis

homeostasis

Maintenance of a dynamic internal constancy

Established via feedback mechanisms

negative feedback

move a physiological measure back towards a set point

positive feedback

effector actions amplifies the

change that stimulated the

effector

variance and standard deviation

the degree of deviation or spread in a distribution about the mean

standard error

standardizes sample

means based upon sample size

degrees of freedom

df = (n1 + n2) – 2

physiology

the functional processes of a living organism

what is the scientific method represents and how does it pertains to experimentation?

it represents a standardized model of experimentation where we can account for lurking variables and prove hypotheses

How is inductive reasoning used in the scientific process?

it is used to discover general principles via the careful examination of specific cases

this is done through experiments following the scientific method

Why is the scientific method used in the investigation of physiological processes?

to observe and measure results, conduct different tests and compare to control variables

can set points be changed?

yes. Different levels of fitness can affect the resting heart rate among individuals

Prostaglandin, a type of hormone, influences the temperature-control center in the hypothalamus. Interestingly, bacterial infections increase prostaglandin synthesis.

What effect do you think prostaglandin has on the set temperature of the human body?
body?

inc body temp

Prostaglandin, a type of hormone, influences the temperature-control center in the hypothalamus. Interestingly, bacterial infections increase prostaglandin synthesis.

Which basic component of the feedback loop for body temperature control does prostaglandin affect?

it affects the integration center of the negative feedback loop

Prostaglandin, a type of hormone, influences the temperature-control center in the hypothalamus. Interestingly, bacterial infections increase prostaglandin synthesis.

What effect does acetaminophen, an antipyretic or fever-reducing drug, have on prostaglandin synthesis?

acetaminophen inhibits prostaglandin from being produced which causes fevers to reduce.

Briefly explain why the human body dedicates so much “time & energy” to maintaining homeostasis?

the body must maintain a stable internal environment bc deviation from the set points can lead to a lot of issues in the body. Feedback loops maintain the set point within the body.

Enzymes are changed by the reactions they catalyze. T or F

False

How does an enzyme increase the rate of biochemical reactions?

they lower the activation energy for the reaction to proceed

Can the presence/increase in certain enzymes in the blood be an indicator of organ/tissue damage?

yes

Phosphatase ____a phosphate group, whereas kinase ____ a phosphate group.

removes; adds

For a single enzyme, _____and temperature are environmental conditions that affect shape and thus performance

pH

________is a toxic byproduct of cellular processes. Catalase manages this byproduct by converting it to _______and oxygen.

Hydrogen peroxide; water

An enzyme is added to a substrate, initiating a reaction immediately. What modification will decrease the duration of the reaction?

add more enzyme

Metal ions, such as magnesium and selenium as examples, are needed for the activity of specific enzymes; these ions are referred to as ____

cofactors

Antacids affect pepsin in what way?

dec effectiveness

Pepsin is produced by the ___ of the stomach. If someone's body did not produce pepsin, digestion of ___ would be impaired.

chief cells; proteins

Enzymatic reactions are strictly unidirectional. T or F

False

what are enzymes?

biological catalysts

most are proteins

some are forms of RNA→ ribosomes

inc the rate of biochemical rxns by lowering the activation energy required for a rxn to proceed

catalase eqn

2H2O2→ (catalase)→ 2H2O + O2

shape of the active site is determined by

amino acid sequence of the protein , this is unique for diff enzymes

specificity

What factors affect enzyme activity

temperature

pH

concentration of enzyme

concentration of substrate

the amount of product is how proportional to enzyme concentration?

directly

catalase fxn

shields cell from damage by breaking down hydrogen peroxide into harmless byproducts

fxns best at high temperatures

which enzymes are found throughout the body

catalase and phosphatase

phosphotase eqn

para-nitrophenol phosphate → phosphotase (takes phosphate)→ para-nitrophenol→hydrolyzed→ para-nitrophenolate

phosphotase fxn

cleaves phosphates from substrates to activate or deactivate enzymes

impt in signal transduction pathways

can be acidic or alkaline → fxns best at diff pHs

20 deg

pepsin reaction

polypeptide + H2O→ pepsin→ polypeptide fragments

pepsin fxn

degrades foods into peptides

inactive then activated by HCl

produced by chief cells in walls of stomach

fxns best at low pH high temp

osmosis

diffusion of water across a membrane

ion channels can

be gated, are passive and selective

cystic fibrosis is the result of…

a mutated chloride channel, resulting in high concentrations of chloride within the cell. This causes water to flow into the cell.

When there are defective chloride channels in the epithelial cells of the respiratory tract, it causes the defective cells to absorb water and trap it inside. The trapped water prevents the mucus from thickening.

What keeps polar molecules from freely crossing the plasma membrane? 

lipids of PM

Water molecules, although not lipid-soluble, can diffuse across the plasma membrane to a limited degree because of …

their small size and lack of net charge.

diffusion

mvmt of solute molecules from high→ low conc

cell membranes are impermeable to

large, charged and polar molecules

tonicity

effect of solution on osmotic mvmt of h2o which changes cell volume and shape

hypotonic

lower osmotic pressure

cell swells

hypertonic

higher osmotic pressure

shrinks

diffusion dependent upon

concentration gradient

permeability of membrane

surface area of membrane

size of molecules

temperature

SA/V ratio inc…

rate of diffusion inc

large surface area, small volume

osmotic pressure

more concentrated solution has higher osmotic pressure

surface area

each side find area, then add up area of all sides

2 mm cube → area is 4

4+4+4+4+4+4=24 cm2

volume

side multiplied by 3

cm3

reflex vs learned response

reflex is an instinctual phenomenon

learned response requires higher brain fxning

transduction

conversion of stimulus energy into graded potentials which our nervous system can interpret

two-point threshold

the smallest separation at which 2 stimuli are perceived as distinct

autonomic reflexes effectors

glands, cardiac muscle, smooth muscle

nystagmus

rapid involuntary mvmt of eyes that may occur from side to side, up and down or rotary

activation of ____ causes a reflex contraction of stretched muscle

muscle spindles

components of reflex arc

sensory receptor

sensory neuron

integration center

motor neuron

effector

reflex arc def

unconscious motor response to a sensory stimulus

somatic reflexes

skeletal muscle, usually are under voluntary control but not during reflex

always excitory

patellar or knee jerk reflex

achilles reflex

plantar reflex

autonomic reflexes ex

either excitory or inhibitory → depends on NT released and receptor type on effector

pupillary light reflex

pupillary skin reflex

positive afterimage

caused by continued firing of photoreceptors

negative afterimages

due to bleaching of visual pigment of affected photoreceptor

ipsilateral reflex

stimulus and reflex occur on same side

contralateral reflex

stimulus and reflex occur on opposite sides of the body

what cues have the best reaction time?

auditory

how do we localize sound?

the cochlea analyzes the frequency of sound which helps us localize sound

sensory acuity

sharpness of sensation

The greater the amount of sensory receptors serving the area, the greater the sensory acuity

what can we understand from the reciprocal of the two-point threshold distance?

The reciprocal represents the portion of the somatosensory cortex that information for the sensory receptors for a given body area