Physiology So Far

What is the study of the function of an organism and its parts, including physical and chemical processes involved?

physiology

The _____ of virtually every body part is suited to the role it plays; that is, structure is the basis of function.

anatomy

The functions of body parts contribute, directly or indirectly, to maintaining _______

homeostasis

Cells -\> Tissues -\> Organs -\> _____ _____

Organ Systems

Human cells are ______

specialists

Extracellular fluid ECF -- body fluid that _____ cells, it is different from intracellular fluid ICF.

surrounds

What is ECF high in?

Na+, Cl-, HCO3-

What is ICF high in?

K+, Mg++, phosphates

ECF is kept separate from ICF by ______ of cells.

plasma membrane

ECF forms the _______ of cells, they are in direct contact with it.

immediate environment

_____ is also called the body's internal environment.

ECF

ECF is divided into _____ and ____ ___.

Plasma, Interstitial fluid

What is the fluid portion of blood, surrounds _____ cells?

blood

____ ____ or tissue fluid surrounds ____ cells?

interstitial fluid, tissue

Plasma or interstitial fluid are separated by the ________.

walls of blood vessels

The smallest vessels, capillaries, have porous walls; thus, the chemical compositions of plasma and interstitial fluid are _______

continually mixing

A change in composition of ____ thus results in a change in composition of the other

one

Homeostasis- keeping the physical and chemical conditions in the ______ nearly constant and ideal for cell life.

extracellular fluid

What are the ECF variables maintained in homeostasis?

temperature, fluid pressure, volume, pH, osmolarity, concentrations of oxygen, CO2, glucose, Na+, K+, Ca++, etc.

Associated with each regulated variable is an ideal value, or ______.

set point

A control system or reflex arc maintains the variable at or near its _______

set point

Receptor- a sensory structure that detects _______

a change in the variable being regulated

Sensory pathway nearly always a nerve cell fiber- route that allows information gathered by receptor to reach the _______

integration center

"Integration center usually nerve cells in brain or spinal cord- compares the sensory information with the _____ and ""decides"" what action to take."

set point

Motor pathway nerve cell fiber or hormone in blood- route that allows integration center to communicate with the ______

effector organs or organ

Effector usually a muscle or gland- performs actions that produce the ______ to the initial change in the variable

response

One trip through the pathway is called a ____

reflex

A protein's 3D shape determines its fxn by determining what will ________.

bind to the protein

Protein binding site- region on the protein surface responsible for holding a _____ to the surface.

ligand

Binding sites have chemical specificity -- one binding site will bind to only one kind of molecule or a few, due to complimentary shape and charge between ligand and binding site.

Different proteins have different ________________, thus different binding site shapes/charges, and different specifications.

3D shapes

Affinity determines how likely it is that a bound ligand will leave the protein surface.

_______- occurs when 100% of the binding sites on a group of identical proteins are occupied by ligands.

saturation

The degree of saturation depends on the _______ of the ligand in the solution and the affinity of the binding site for it.

concentration

Competition -- if two different ligands can bind to a binding site, they ________ for the available sites.

compete

Binding site functions: Aggregation of proteins into organized structures, as _______, detection of chemical messengers.

enzymes

Allosteric modulation activation, inhibition, modification- the binding of ligand A a modulator molecule to its site alters the shape of the binding site for __________.

ligand B on same protein

Covalent modulation modification- changes the shape of the binding site by attaching, via a ______ bond, a chemical group to the protein: Requires an enzyme, usually, a phosphate PO~4~^3-^ is the group attached; if so, the process is called phosphorylation and the enzyme is called protein _________.

Covalent, Kinase

A modulator turns on the protein kinase

which then covalently attaches a PO~4~^3-^ group to the protein so that the protein can bind its substrate

The enzyme phosphoprotein phosphatase removes the PO~4~^3-^ group, returning the protein to its _________

original shape

The lipid bilayer of the plasma membrane is a barrier to water and to water-soluble substances

Aquaporins- pores in proteins that permit rapid passage of ______ through plasma membranes but exclude other substances

water

Membrane proteins with _______, through which ions can diffuse

pores/holes

"The _______of the channel, charges on its amino acids, and more complex ""selectivity filters"" give it specificity : e.g., a sodium channel allows only Na+ to pass thought it"

diameter

At any particular time, a given gated channel is either open completely or ______

closed

A cell's permeability to Na+ at any given instant depends on 1 the ________ it possesses, & 2 the percent of them that are open

number of sodium channels

Ligand-gated channels: open in response to the binding of a ______ to a receptor on or near the channel

ligand

Voltage-gated channels: open in response to change in the ________ called a membrane potential across the plasma membrane

voltage

Mechanically gated channels: open in response to being physically _______

deformed

Secondary _____ transport can be co-transport or counter-transport example: sodium co-transport.

active

"Secondary active transport: example sodium co-transport/ this is the way by which glucose and most amino acids are transported against ________ from the lumens of the intestine & kidney tubules into cells in the wall of the intestine or kidney tubule, in contrast, ""normal"" transport of glucose into nearly all body cells occurs by facilitated diffusion, which does not move glucose against its concentration gradient."

their concentration gradients

This process requires cellular energy but rather than directly moving the glucose, the energy is used to establish a concentration gradient for Na+

secondary active transport

This Na+ gradient, along with a non-energy-using carrier molecule, is then used to transport glucose across the membrane; mechanism---the lumen of the gut or kidney tubule is lined with cells that are near blood capillaries; Na+ is actively transported by the energy-using Na+ - K+ pump from the cells into the blood _________

capillary

This process requires cellular _____, but rather that directly moving the glucose, the energy is used to establish a concentration gradient for Na+, this Na+ gradient, along with a non-energy-using carrier molecule, is then used to transport glucose across the membrane

energy

This Na+ transport establishes a conc. gradient for Na+, with a higher Na+ concentration in the gut lumen and a lower Na + concentration within the cell, but the membrane is not permeable to Na+ unless Na+ is bound to a non-energy-using carrier; however, this carrier will not allow Na+ to diffuse across the membrane unless the Na+ is accompanied by a molecule of _______

glucose

This process requires cellular energy, but rather than directly moving the glucose, the energy used to establish a _______ _____ for Na+

concentration gradient

This Na+ gradient, along with a non-energy-using _____ molecule, is then used to transport glucose across the membrane mechanism.

carrier

Na+ concentration gradient established, but no diffusion of Na+ from gut _____ into cell.

lumen

Na+ and _____ bind to the carrier.

glucose

With the help of the carrier, Na+ can diffuse across the membrane, and because of the orientation of the Na+ concentration gradient, it goes from the lumen of the gut into the ________

cell

"A glucose molecule is ""pulled"" through the membrane along with the Na+; thus glucose also moves _____ even though this is against the glucose concentration gradient, not that this specific step does not require ATP"

into the cell

"Glucose can now enter the blood capillary via the ""normal"" way of moving it"

facilitated diffusion

The carrier co-transporter protein is called a symporter because Na+ and glucose move in the _____ direction.

same

____ ____ _____- involves the use of an electrochemical gradient usually for sodium and protein cotransporters are classified as symporter or antiporters.

Secondary Active Transport

_____ transport substance in same direction as a driver ion like Na+

symporters

Antiporter carrier proteins also exist that move Na+ and the other to-be-transported substance in ______ directions in this case, the secondary active transport is also called sodium counter-transport assuming Na+ is the driver ion.

opposite

______ transport substance in opposite direction of a driver ion like Na+

antiporters

What is a chemical secreted into blood that influences the function of target cells in other body locations?

Hormone

Advantage to using blood as a delivery vehicle for messenger molecule is ______________________________________.

sometimes the message needs to go to a large number of cells simultaneously

Disadvantage to using blood for messenger molecule delivery is _______________________________________

this system is slow, a slow way to do it

General rule: Hs regulate metabolic fxns; neurotransmitters regulate muscular and _____ activities

secretory

roosters caponized with time, atrophy of sexual accessories and ______ in sexual performance

Decline

roosters caponized and testes put back in body cavity, (no nerves attached), look and perform like _____male

Normal

Conclusion: ______ produce a substance carried by the blood that influences other body parts & fxns

testes

Bayliss and Starling experiment (1902): Surgically isolate a length of small intestine so that all nervous connections are cut while keeping blood supply intact Put stomach acid into isolated intestinal (duodenal) segment Result: ______ produced pancreatic juice Conclusion: chemical produced by duodenum is carried by blood to pancreas, where it stimulates release of pancreatic juice

pancreas

Paracrines – secreted into ECF (typically interstitial fluid) and influence ___________ target cells of a different type

nearby/neighboring

Autocrines – secreted into ECF (typically interstitial fluid) and influence the____ cells that produce them

same

Neurohormone – hormone released into blood by endings of ______ cells

nerve

Endocrine gland – a ________ gland

ductless/gland with ducts

Endocrine system - nervous system (NS) relationships: • NS secretes some Hs • NS controls secretion of Hs by many glands • Hs alter ________________

nervous system function

Other endocrine complications: • a single gland often secretes more than one hormone; for example, ______________

anterior pituitary secretes at least 6 hormones

a single H is sometimes secreted by more than one gland; for example _______________ is secreted by the hypothalamus & pancreas

somatostatin

some endocrine glands also have distinct, nonendocrine functions; for example ____________

kidney secretes 3 hormones

H _______– only certain cells, target cells, respond to a given H because other cells do not have receptors for the H

specificity

Three chemical classes of Hs 1. Amine Hs: • derived from the amino acid __________ (or tryptophan; NEM) medulla cortex Adrenal gland • include the thyroid metabolic hormones -- thyroxine (T4) & triiodothyronine (T3) • include the adrenal catecholamines -- epinephrine and norepinephrine, secreted by the adrenal _________ (these are also transmitters in the nervous system) • include dopamine

tyrosine, medulla

2. Peptide and protein Hs (most Hs, including all from the _________________) • amino acid (aa) chains; from 3 aa to nearly 200 aa • peptides have < 50 or < 100 aa, depending on whom one consults • synthesis: cell builds a larger, inactive molecule ( a prohormone); this is later cleaved enzymatically, with one of the resulting pieces being the active H

pituitary