BIO349

Homeostasis

The body's tendency to maintain stable internal conditions despite external changes.

Extracellular fluid

Fluid outside the cells but within the body, important for cellular function.

Unicellular vs

Contrasting single-celled organisms with multicellular organisms that have specialized cells for specific functions.

Boundary organ concept

The idea that organs play a crucial role in maintaining homeostasis by acting as boundaries.

Feedback loops

Mechanisms that regulate physiological processes through positive or negative feedback.

Feedforward mechanisms

Anticipatory processes that prepare the body for expected changes.

Cell Membrane Function

The selective barrier that controls the movement of substances in and out of the cell.

Fick's Law

Describes the factors influencing the rate of diffusion across a membrane.

Membrane Proteins

Integral proteins that facilitate transport, enzymatic activity, and signal transduction across the cell membrane.

Signal Transduction

The process by which extracellular signals are transmitted into the cell to elicit a response.

Ultimate outcome of EPSP and IPSP

EPSP (Excitatory Post-Synaptic Potential) and IPSP (Inhibitory Post-Synaptic Potential) determine whether a neuron will fire an action potential or not.

Temporal vs Spatial Summation

Temporal summation occurs when a neuron fires action potentials at a high frequency over time, while spatial summation involves the simultaneous input from multiple presynaptic neurons.

Pre-synaptic Inhibition

Pre-synaptic inhibition limits the amount of neurotransmitter released from the presynaptic neuron, affecting signal transmission.

Acetylcholine Breakdown

Acetylcholine is broken down by acetylcholinesterase, removed through urine, diffused into blood, and recycled for further use.

Sensory Receptors

Sensory receptors include photoreceptors (eyes), mechanoreceptors (baroceptors, proprioceptors), osmoreceptors, thermoreceptors, nociceptors (pain), and chemoreceptors.

Generator Potential

Generator potential is a stimulus-sensitive, nonspecific cation channel that initiates sensory signal transduction.

Exteroceptors vs Interoceptors

Exteroceptors detect changes outside the body related to special senses, while interoceptors monitor internal body conditions.

Autonomic Nervous System

The autonomic nervous system regulates involuntary functions through sympathetic (fight or flight) and parasympathetic (rest and digest) divisions.

Adrenergic Receptors

Adrenergic receptors, including Alpha 1, Alpha 2, Beta 1, and Beta 2, respond to epinephrine and norepinephrine to modulate physiological responses.

Muscle Physiology

Skeletal muscles are striated, cardiac muscles are striated and interconnected by desmosomes and gap junctions, while smooth muscles lack striations and can function as multi-unit or single-unit structures.

Which kind of control mechanism takes precedence when both are active: local or long distance?

Local to dilate, long distance to vasoconstrict

local takes precedence over long-distance

transport

ion channels, transport-pumps, symports, anitports

ex. na/k pump

intercellular joining

cell junctions

ex. gap junctions, tight junctions, desmosomes

cell-cell recognition

glycoproteins, satellite antenna

blood group types

enzymatic activity

catalyze reactions

ex. acetylcholinesterase

signal transduction

hormone or neurotransmitters, activating nearby or secondary mechanisms

ex. insulin receptors

fick’s law

info on diffusion through a singular membrane

how molecules from areas of high concentration move to lower concentrations over time

Microvilli

increase surface area of membrane

Resistance is based off

solubility and size

what can thickness impact

doesnt change itself but other things can

bigger difference in concentrations, faster a molecule can move

surface area- larger then more molecules can move across

CAM

majoe histocompatibility complex

through there interfacial surface, only takes in molecules they were meant to take

Types of mediated transport

carrier-facilitated channel

active transport- atp

endocytosis- takes in energy

exocytosis- releases energy

carrier proteins do what when attatched to proteins

changes shape to perform function

what determines rate of transport?

concentration gradient

Where are GLUT 4 transporters found at?

Skeletal muscle cells and adipocytes

How are GLUT 4 transporters incorporated into the cell membrane?

exocytosis

how is insulin made and released from beta cells?

endocrine function-released directly into blood in response to elevated glucose level

Process to maintain net diffusion of glucose into cell

Facilitated diffusion; carrier protein at membrane binds to glucose and alters shape to make transfer easier along gradient

Electrical potential

charge difference inside and outside of cell, negative outside creates the potential across the membrane

Chemical potential

difference of ion or molecule concentration between the inside and outside of cell

Electrical and Chemical potential

energy gradient that affects how molecules move across cell membrane and impact processes like nerve signaling, contractions, nutrient transport

power activities while maintaining environment

Tight junctions

prevents inside and outside from leaking

symport

two dif types of molecules or ions move in same direction using energy from movement of one moelcule down its concentration gradient to power the movement of the other molecule, moveing in same direction across membrane through a transport protein into or out of cell

ex. sodium-glucose symporter which transports into the cell lining of small intestine

antiport

molecules or ions transported across membrane in diff directions and movement of one powers the other, one moved out while the other moves in from a single transport

ex. sodium-potassium pump (sodium out while potassium in)

T/F glucose absorption into epithelial cells lining the intestine relies on normal function of Na-K pumps

true

T/F rate of entry into adipose cells is discreetly proportional to the permeability of the plasma membrane

true

T/F glucose absorption through the Na+ glucose symporter will increase indefinetly as glucose concentration increases

false

T/F glucose diffusion is often directly controlled by voltage-gated channels

false

glucose entering beta cell

diffusion happens when gradient is kept then makes ATP

tenacity

solute concentration in a solution and comparing to another

osmolarity

dilluteness of a solution based off addition of water

gap junctions

direct

small molecules can pass between

indirect comm/contact

signal from point a to point b w/o direct contact with target cell

short distance: autocrines and paracrines

long distance (into blood to circulate body)- hormones and neurohormones

Paracrines

cytokines- regulate immune function (ie. macrophage release interlucins to help with immune response to signal outsider)

eicosanoids- lipid based: derived from arachidonic acid; prostaglandin

arachidonic acid

may act as second messenger, can be converted into a variety of paracrine messages

leukotrienes- asthma and anaphylaxis

prostaglandins- inflammation, pain, fever, smooth muscle function

thromboxanes- blood clotting

neurotransmitters

chemicals secreted by neurons that diffuse across a small gap to target cell. uses electrical signals too

neurohormones

acetylcholine, norepinephrine, dopamine, serotonin, glutamate, glycine

steps in signal transduction: target cell response

signal molecule binds to recceptor protein activated intracellular signal molecules alters target proteins create response

lipho-

liphophilic- message enters cell, often activates gene, slower response

lipophobic- message cant enter cell

are all lipophilic hormones steroidal?

where might the receptor be located in the target cell for a lipophilic chemical message?

whihc stage of protein synthesis is influenced by lipophilic hormones?

what kinds of proteins might be made, and how would they be used in the cell?

integrin

connects extracellular matrix to cytoskeleton

receptors binding can change shape of cell

protein kinase

phospholarize, add or remove phosphate form from a molecule

cyclic-AMP

2nd messenger or activate protein kinase A

signaling pathway: binding of epi to g

inactive g protein- activates, etc etc

autonomic nervous system

sns and pns

sns

inhibitory

pns

excitatory

deactivating messengers

in urine, destroyed by digestion, broken down by extracellular enxymes, transported into other cells

removed, broken down

Stresses

metabolic: lack of nutrients to stimulate response

emotional: nerves, pns

exercise/physical stress

endocrine functions

regulation of energy metabolism, water and electrolyet balance, adapt to stress, growth and dev, reproduction, regulate rbc wb and platelet production, digestive system functions

hormone secretion mechanisms

direct- neural-adrenal medulla

negative feedback- humoral stimuli- parathyroid gland

hypothalamic control- hormonal sitmuli- anterior pituitary gland

integration levels

Hypothalamus (control/integration system of endocrine systems, releases or inhibits hormones)– pituitary (specific responses based of specific target cell)– endocrine gland

Releasing & inhibiting factors– tropic hormones– response in target cells

renin-angiotensin-aldosterone system in regulation of water balance

profusion, kidney recognizes drop, angiotensin converting enzyme (1 into 2), increase thirs response

lipid soluble (hydrophobic)

steroids- derived from cholestrol and synthesized in smooth er

thyroid hormones- t3 and t4 (not steroids but soluble)

water soluble (hyrophillic)

modified amines: catecholamines, histamine, serotonin, meltaonin

hyposecretion

too little hormone activity

increased removal from blood, lack of target cell receptors, lack of proteins

hypersecretiion

too much hormone activty

reduce binding or removal from blood plasma

decreased metabolic inactivation

decreased excertion

alarm phase (fight-or-flight)

immediate short-term response to crises

sympathetic

1. mobilization of glucose reserves

2. changes in circulation

3. increases in heart and respiratory rates

4. increased energy use by all cells

resistance phase

long-term metabolic adjustments

1. mobilization of remaining reserves: lipids are released by adipose tissue, amino acids released by skeletal muscle

2. conservation of glucose: peripheral tissue (except neural) breaks down lipids to obtain energy

3. elevation of blood glucose concentrations: liver synthesizes glucose from other carbs, amino acids, and lipids

4. conservation of salts and water

exhaustion phase

collapse of vital systems

causes may include:

exhaustion of lipid reserves, inability to produce glucocorticoids, faliure of electrolyte balance

can be min or extended but pretty short

what gets glut 4 into vesicles?

golgi apparatus

afferent

sensory pathway, imcoming

efferent

motor pathway, outgoing

somatic: skeletal muscles, stretch

autonomic: sympathetic and parasympathetic

graded potentials

stronger stimulus= stronger graded potential

weaken over distance

• Graded potentials (alone, singular) mostly dont reach threshold

  • When it is met, action potential formed (all or nothing)

  • Trigger zone is threshold

depolarization

excitatory post-synaptic potential

hyperpolzarization

inhibitor post-synaptic potential

K+ and Na+

k-hyper

na-depolar

Movement of different ions to cause different changes within the membrane (depolarization, more positive/ repolarizing, more negative/ hyperpolarization, brings further from threshold)

temporal summation

over time, faster frequency

spatial summation

multiple at same time

inhibtion

pre-synaptic inhibition limits amount of neurotransmitter released

sensory receptors

photo- eyes

mechano- all over

thermo- temp

noci- pain

chemo- chemical

senses

taste, scent, smell, touch, hear

exteroceptors

interoceptors

somatosensory pathways

synapse in thalamus'

stimulates on left side but reaches right side of brain

perception of sensory info

• sensory acuity

  • field size: amount of area at cortex, how much space can dedicate to recieving signals and pinpoint stimulus

stimulus intensity

frequency and population code

-how fast ap are being generated and sent (individual)

-how many neurons are stimulated that can converge