People's: Homeostasis and Cell Membrane

Is energy required in steady state? In Equilibrium?

may or may not, no energy required

3 control systems necessary for maintaing homeostasis

sensor, integrating center, effector

Negative feedback: effector opposes or reinforce change?

In positive, there is a ___ to _ the system

opposes, endpoint, reset

Pathological consequences of excessive heat on tissue damage and biological function

tissue: apoptosis and denaturing proteins

Biological: high rate of rxns, high CNS

PAthological consequnces of excessive cold: tissue and biological function

Tissue: dentaturing proteins

Biological: lowered rate of rxn, low CNS, low Cardiovascular, low skeletal muscle function

the core is __ regulated at _ degrees, at the sacrifice of ?

tightly, 37C, shell

Where are the sensors/thermoreceptors in our central system?

hypothalamus, abdominal cavity (core temp)

Integrating center of control system for human

hypothalamus

How does sweat glands help?

dissipate heat, evaporative cooling

In cold: the skin would vasoconstrict or vasodilate? how would this affect blood flow?

vasoconstrict, lower flow

Response to cold besides behavior, decreased blood flow, shivering, is ?

How?

Nonshivering ___ in _ fat: ?

increased metabolic rate

epinephrine and TH release

fat breakdown

thermogenesis in brown: high mitochondria

what causes fever?

macrophages → pyrogrens (IL-1) → prostaglandins (PGE2) in hypothalamus → increases set point

what is hyperpyrexia and what is the consequence?

very high fever (107): seizures

How does heat exhaustion cause fainting?

sweating, fluid loss, lower blood volume, low bp

possible mechanism of heat stroke

GI vasoconstriction, ischemia, endotoxins from intestinal bacteria released into blood, decreased blood flow

CNS: delirium, coma, no sweating: indiciative of?

heat stroke

amphiapathic

polar and nonpolar

phospholipid

3 carbon glycerol backbone, 2 fatty acids, phosphate and alochol

cholesterol in the cell membrane?

decreases fluidity

the carbohydrates of cell membrane, such as ___ and _, do what?

glycolipids, glycoproteins, cell to cell interaction extracellular

simple diffusion occurs by? Usually what?

random thermal motion, nonpolar/hydrophobic

Factors determinng diffusion trhough cell membranes: size, polarity

small, nonpolar

Osmosis stops when

hydrostatic pressure equals osmotic

150 NaCl osmolarity:

150 mM glucose osmolarity:

300, 150 moles

What does not cross readily? what does?

Na+, K+, urea does

150 nM NaCl, 300 mM urea osmolarity adn tonicity

150 nM glucose, 100 M urea

600 osmo, 300 tonicity

250 osmo, 150 tonicity

hyponatremia/water intoxication cause?

low salt

kidney and liver disease can be related to ?

tonicity

amino amino acids and sugars are transported through?

carrier proteins: transporter/exchangers (facilitated diffusion)

carrier proteins: transporter and substrate size?

passive, too big to cross

transport maximum velocity

opening at 100%, all enzymes used

chemical specificity of facilitated diffusion

only specific molecules that fit

ion channels: passive or active, substrate size, flux rate

passing: gradient, small, very high

3 main types of ion channels

NT, voltage, stretch activation

vesicular transport is?

endocytosis: pinching off + exocytosis, releasing

pinocytosis vs phago

pino is small, phago is large

why use second messengers? (3)

intracellular (for molecules cant cross), amplification, speed

hormone regulation of gene expresison: where are receptors? Speed?

inside cell cytosol/nucleus, slow (hours to days) and long lasting

ion channels: __ action

pathway

indirect

hormone → receptor → g protein → effector protein → second messengers (CAMP) → channel

Calcium pathway second messenger

GPCR (g protein couple receptor) → IP3 → ER/SR increased Ca2+ production and expulsion through channel → calmodulin (in cell) → activates protein kinase that phosphorylates proteins (Ca, CaM, PK together)

tyrosin kinases?

attach phosphate group to tyrosine residues in proteins (is a receptor)

phospholipase C/ insitol triphosphate (IP3)

Hormone → receptor → PLC (phospholipase C) →

• IP3 → intracellular calcium storage sites → exocytosis of Ca2+ → biological effects

• DAG (diaglycerol) → protein kinase C → phosphorylates enzymes for activation

adenylyl cyclase /cyclic AMP:

• Hormones for Receptor stimulatory and receptor inhibitory of G proteins stim and inhibitory

• G protein + adelync cyclase → cAMP ->PDE (5’AMP)

• cAMP activates protein kinase A → phosphorylates proteins

what inactivates cAMP

phosphodiesterase