Human Physiology Unit 1

scientific method

hypothesis (testable), reproducible data, quantitative measures, control & experimental groups, peer reviewed

homeostasis

maintenance of relatively stable internal environment, includes sensor, integrating center, and effector

sensor

detects deviation from set point

integrating center

controls activity (effector) based on sensor

effector

adjustments to counter change happening (feedback loop)

negative feedback

most common, response COUNTERACTS change, back towards set point (temperature, blood glucose)

positive feedback

amplifies change, output of effector increases and furthers change from set point (childbirth)

antagonistic

opposing effectors on same factor, push-pull (hot=sweat, cold=shiver)

intrinsic homeostasis

cells within an organ sense change and signal to neighboring cells, all then act accordingly

extrinsic homeostasis

cells outside an organ like endocrine or nervous system responding to stimuli or change

body hierarchy

cell → tissue → organ → organ system → organism

nervous tissue

communication, regulate/integrate

neurons

high speed, electrical

neuroglia

support neurons

epithelial

covers and lines, absorb and secrete, barrier and protection - forms exocrine glands

connective tissue

structure and support, transportation, large extracellular matrix

specialized CT - adipose

large cells (adipocytes), most of their interior covered by a droplet of triglycerides

specialized CT - cartilage

cells found in small cavities (lacunae) in matrix

stem cells

creates highly specialized tissues

totipotent

embryonic stem cells, can form into all tissue

pluripotent

embryonic stem cells, can form most tissue, not placental or supporting tissue

multipotent

adult stem cells, undifferentiated cells in some organs, maintain and repair tissue

body fluid make up

60% H2O, 40% intracellular, 20% extracellular, separated by membranes and can exchange fluid

intracellular

cytoplasm

extracellular

interstitial fluid (80%) and plasma (20%)

covalent bond

two or more atoms share pairs of valance electrons, strongest bond, polar (equal share) or non-polar (not equal sharing)

ionic bonds

one atom gives electrons to another - fills both valance shells, strong electrostatic attraction (oppositely charged atoms), can dissociate in water

hydrogen bonds

weak attraction between polar molecules, - end to + end

acidic solution

releasing H+ ions when mixed with H2O (increase H+)

alkaline (basic) solution

solutes bind to H+ molecules when mixed with H2O (decreasing H+)

blood pH

between 7.4 ± 0.5

below normal blood pH

acidosis

above normal blood pH

alkalosis

carbohydrates

hydrogen (1), oxygen (2), carbon (1)

monosaccharides

one carbon ring

disaccharides

two carbon rings (by covalent bond)

polysaccharides

polymer of glucose, glycogen, starch/fiber

triglycerides

three fatty acids, backbone of glycerol

saturated triglycerides

single covalent bond, carbon binds 2 hydrogen

unsaturated triglycerides

double covalent bond, carbon binds one hydrogen

phosolipids

glycerol molecule attached to phosphate group (3 carbons), polar and non-polar so amphipathic, lowering surface tension on water and allows hydrophilic substances to suspend in polar solvents

prostaglandins

type of fatty acid, communication molecules, pro-inflammation, ovulation, uterine contractions, produced in almost all organs

primary protein

sequence of amino acids in polypeptide chain

secondary proteins

helix shape, hydrogen bonds between peptide chains

tertiary proteins

twisting/folding of polypeptide chains, chemical reaction of side chains

quaternary proteins

bonding/interacting of multiple polypeptides

glycoproteins

protein + carb (cell membranes)

lipoproteins

protein + lipid (carrier molecule in blood)

nucleotides

five carbon sugars, phosphate group, nitrogenous base

bulk transfer

large amounts of extracellular fluid and molecule exchange

plasma membrane

separates extracellular/intracellular and regulates movement (selective mechanical barrier), phospholipid bilayer

peripheral proteins

embedded on one face of membrane (structure, transport, receptors, self markers)

integral proteins

span across membrane (structure, transport, receptors, self markers)

peroxisomes

membranous sacs, H2O2, break down fatty acids, oxidative reactions (detoxification)

lysosomes

breakdown, digestive enzymes, bacteria, old organelles, food molecules

transcription

in nucleus, DNA → RNA, promoter region → transcription factor binds = RNA polymerase and copying

translation

in cytoplasm, RNA → protein, final sequence codes, ribosomes bind to mRNA and read codons, tRNA holds complementary sequences (anticodons), rRNA is structural component of ribosomes

necrosis

pathological cell death, damages adjacent cells

apoptosis

homeostatic cell death (programed/controlled), doesn’t damage other cells

effects of pH on reactions

changes shape of protein/active site

effects of substrate concentration on reactions

more substrate = rate of reaction increase until saturation

enzyme modulation

some enzymes produced as zymogens (need to be activated) by phosphorylation or dephosphorylation

coenzymes

additional small molecules to aid reaction, derived from water soluble vitamins, H+ atoms and others between enzymes

cofactors

covalently bonded - TEMPORARY, metal ions, attach to enzyme causing shape change to allow substrate/enzyme binding

endergonic reactions

reactions that need input of energy (i.g. photosynthesis)

exergonic reactions

reactions that produce energy (i.g. break down glucose into CO2 and water to produce energy)

ATP hydrolysis is an exergonic reaction driving endergonic reactions in the body

metabolism

chemical reactions in the body maintaining homeostasis

anabolism

requires the input of energy to synthesize large molecules (synthesize and store)

catabolism

releases energy by breaking down large molecules

cori cycle

lactic acid (produced in skeletal muscle) → liver (pyruvic acid and NADH, by LDH) → back to muscle (creates new glucose)

white adipose tissue

fat stored as triglycerides

lipolysis

breakdown of triglycerides to fatty acids (can enter blood for energy) and glycerol (taken up by liver) by lipase enzyme

beta (fats) oxidation

triglycerides to acetyl COA, mitochondrial matrix, 108 ATP

brown adipose tissue

thermogenesis, uncoupling proteins - H+ across w/out concentration gradient = more ATP

ketone bodies

lipolysis rate faster used than produced via beta oxidation, liver converts fatty acids to acetyl COA then ketone bodies (into blood/plasma = more acidic)

amino acid metabolism

amino acids from diet that body can’t reproduce, can be used to make ATP, excess amino acids = carb or fat storage

transamination

taking away amine group, amino acid → keto acid

osomolarity

high to low (WATER concentration) and low to high (SOLUTE concentration), solute concentration increases = osmotic pressure increases

isotonic

no net movement, same solute concentration

hypotonic

solute in cell is higher than outside so water goes into cell (swelling)

hypertonic

solute in cell lower than outside so water moves out of cell (shrink)

osomoreceptors

hypothalamus detects increase in osmolarity (solute concentration)

i.g. dehydration so thirst or ADH (less output in urine)

transcellular (epithelial)

across cell itself, cytoplasm

paracellular

between epithelial cells

tight junctions

seal between adjacent cells, limit passage

desmosomes

patches holding two cells together, intermediate filaments, resistant to stretch

adherins

“glued” together by special proteins, cadherin, i.g. heart muscle cells held together

just K+

-94 mv, equilibrium

just Na+

+60 mv

resting membrane potential

-70 mv, neurons and muscle tissue is highly excitable (rapid change in membrane potential)

gap junctions

adjacent cells passing ions and regulatory molecules through channels

paracrine signaling (local)

cells in organs secrete molecules that diffuses through extracellular matrix to target tissue/cell

autocrine signaling

cell acts on itself as target

synaptic signaling

neurons regulate/stimulate target cells through synapse (gap), releasing neurotransmitters

endocrine signaling

hormones enter blood to target receptors

second messengers

target cells with receptor proteins that binds to signaling molecules

G-proteins

alpha, beta, gamma - alpha subunit disassociates when signal molecule binds to receptor and travels to effector protein (enzyme or ion channel), GDP is released and hydrolyzed by alpha (alpha then moves back to beta and gamma)

cAMP

g-protein couple to enzyme, g-protein process but when binding to enzyme activates second messenger/response inside cell/adjacent cells, then open/close ion channel occurs