chapter 1 intro to physiology and homeostasis

What is the scientific method?

humans understanding as to why things work, such as the human body

Why is the scientific method important?

process for explaining the world

Provide an objective approach to conducting experiments to see if what you believe is true

limits bias

steps of the scientific method

make observations

form a testable hypothesis

design and conduct experiments or make more observations

analyze the data

reject or accept hypotheses

Results must be replicated many times before a conclusion is accepted

Several verified hypotheses may become a general theory

physiology

study and function of living things

emphasized on mechanism

Explanations are in terms of meeting a bodily need

structure-function relationships of the body

homeostasis

maintenance if a relatively stable internal environment

essential for the survival and function of all cells and organisms

controlled by negative feedback loops

consequence of failing to maintain homeostasis

sickness and death

pathway of systems action to maintain homeostasis

sensor, integrating center, effector

sensor

detects deviations in a condition away from a specified level (set point)

integrating center

controls the activity of the effectors based on the input from the sensors

regulate around a set point

can increase or decrease effector action to counter the change in a set point

effector

makes the appropriate adjustments to counter the change

many times operates by feedback loops

negative feedback loop

change in condition leads to a response that counteracts that change

most common type of physiological response

regulation around a set point

trying to back to said set point

continuous/ ongoing process

positive feedback

effectors increase the change that is occurring

gettning FARTHER away from the set point

An example of positive feedback

blood clotting

puberty in women

contraction of the uterus

intrinsic mechanisms of homeostasis

built into the organs being regulated

molecules that cause vascular dilation/contraction

Cells within the organ sense a change and signal to neighboring cells to respond appropriately

extrinsic mechanisms of homeostasis

outside of the organ

endocrine

nervous system

Both systems heavily regulate the activities of the body

antagonistic effectors

push and pull

increase activity of one effector will decrease acitivity of another antagonist

sweating, shivering

maintains varibales w/in a certain normal range, aka dynamic constancy

example of antagonistic effectors

you are cold, bundle up, then you get too hot, sweat, take layers off, then cold again, and it continues

hierarchical of the human body

cells

tissue

organ

organ system

organism

muscle tissue

specialized for contraction

skeletal muscle tissue

voluntary, striated, at the end of bones

cardiac muscle tissue

involuntary, striated, in the heart walls

smooth muscle tissues

not striated, involuntary, digestive tract, blood vessels, bronchioles

forms sheets that interlock and form junctions

nervous tissue

made up of neurons that conduct and generate electricity

send and recieve informaiton

regulates and integrates various physiological systems

Neuroglial cells that support neurons and have many different purposes

information-> dendrite-> cell body->axon-> anywhere in body

epithelial tissue

covers body structures, lines, organs, and tracts

apical: top side with cilia

basement: bottom part that attaches to connective tissue

absorption

excretion

barrier

protection

forms exocrine glands

connective tissue

large amt ECM and low amt cells

connective tissue proper

ECM contains protien fibers and gel like ground substance

connection, structure, support, transportation

loose connective tissue

made via collagen, located in the ground substance, provides space for blood vessels and nerve fibers

dense regular connective tissue

collagen fibers parallel to each other, densly packed together in ECM leaving little room for cells and ground substance

located in tendons and ligaments

dense irregular connective tissue

forming through capsules and sheaths around organs, dense-packed collagen fibers in different ways to resist force

adipose connective tissue

lose, fat brekadown, nucleus in the corner

cartilage

condrocytes, supportive and protective, forms precouser to many bones, located at joints and bones

bone

connective tissue

lamellar layers, osteoblasts in lacunae that turn into osteocytes, suppliedwith blood via canliculi then into osteons

blood

connective tissue

1/2 volume is ECF aka plasma

organ system

group of organs that work together to perform a specific function

digestive

urinary

integumentary

reproductive

types of stem cells

totipotent, pluripotent, multipotent

totipotent

can become anything

pluripotent

just embryonic cells

can produce all of the body cells except for those that can contribute to the placenta

multipotent

adult stem cell

less differentiated

red bone marrow

function to repair and maintain tissue

body fluid compartments

intracellular and extracellular

65%water intracellular

separated by the plasma membrane

35% extracellular

extracellular matrix contains plasma and interstitial fluid and communicates via blood capillaries and kidneys