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physiology
the study of the normal functioning of a living organism & its components parts (including its chemical / physical processes)
glands (made of epithelial cells) secrete chemicals signals (hormones) into the blood & distributed by circulation
describe long distance communication
atoms → molecules → cells → tissues → organs → organ systems → organisms
what are the levels of biological organization?
pathophysiology
the study of the body functions in a diseased state
homeostasis
the maintenance of a relatively constant internal environment
circulatory
transport materials between all cells of the body
digestive
convert food into particles that can be transported into the body
eliminate some wastes
endocrine
coordinate body functions through synthesis / release of regulatory molecules
immune
defend against foreign invaders
integumentary
protect from external environment
musculoskeletal
support & movement
nervous
coordinate body functions through electrical signals / release of regulatory molecules
reproductive
perpetuate the species
respiratory
exchange oxygen & carbon dioxide between the internal / external environment
urinary
maintain water & solutes in the internal environment
eliminate waste
what are the ten organ systems & their functions?
input signal → integrating center → output signal → response
what are the components of a simple control system?
negative feedback loop
a pathway in which the response opposes / removes the stimulus
positive feedback loop
a pathway in which the response reinforces the stimulus rather than decreasing / removing it
feedforward control
anticipatory responses to changes
emergent properties
properties that cannot be predicted to exist based only on the individual components
appropriate receptor proteins
essential to cells’ response to chemical signals
nervous & endocrine
what organ systems are involved in the reflex control of homeostasis?
local control system
the (chemical) response is restricted to the region where the change took place
reflex control system
long-distance pathway that uses the nervous system & endocrine systems
input signal → integrating center → output signal → response
what are the components of a simple homeostatic control system?
the site of most ATP synthesis
mitochondrion function
modifies / packages proteins
golgi apparatus function
assemble amino acids into proteins
ribosome function
site of fatty acid / steroid / lipid synthesis
smooth endoplasmic reticulum function
site of protein synthesis
rough endoplasmic reticulum function
small, spherical storage vesicles that contain powerful digestive enzymes
function of lysosomes
contain enzymes that break down fatty acids / foreign materials
function of peroxisomes
store genetic information & act as the cell’s “control center”
function of nuclei
direct DNA movement during cell division
function of centrioles
biorhythms
regulated variables that change & have repeating patterns / cycles
acclimatization
the natural adaptation of physiological processes to a given set of environmental conditions (it occurs naturally).
plasma
interstitial fluid
what are the two extracellular fluid compartments in the body & what are their locations?
acclimation
the artificial adaptation of physiological processes to a given set of laboratory conditions
form barriers
separate biochemical processes
prevent movement of materials
what are the functions of compartments in the human body?
compartment
a separate section or an enclosed structure
binds to:
calmodulin: alters enzyme / gating of ion channels
other regulatory proteins: alters movement of contractile proteins (cytoskeleton) & triggers exocytosis
ion channels: entry into fertilized egg initiates development of embryo
function of Ca²+ ions
physical isolation
regulation of exchange with the environment
communication
structural support
what are the functions of membranes?
cyclooxygenase (COX 1 & COX 2)
responsible for the production of prostaglandins & thromboxanes
nitric oxide (NO): acts as neurotransmitter and neuromodulator in brain; produced in epithelial cells; diffuses & causes vasodilation
carbon monoxide (CO): targets smooth muscle & neural tissue
hydrogen sulfide (H₂S): relax blood vessels — can be derived from garlic
the three gases that serve as signal molecules & their functions
cell
the functional unit of all living organisms
down-regulation
a decrease in receptor number; can be removed from the membrane through endocytosis
desensitization
decreases cell response (binding a chemical to the receptor protein)
up-regulation
the target cell inserts more receptors into its membrane
cell adhesion molecules (CAMs)
membrane-spanning proteins responsible for cell junctions & transient cell adhesion
tight / occluding junctions: claudin, occludin, & connexin
anchoring junctions: cadherin & integrins
gap / communicating junctions: connexin
what types of proteins form the three types of cell junctions?
retinitis pigmentosa: improper protein folding of the rhodopsin receptor in the retina
familial hypercalcemia: calcium censor in the parathyroid gland fails to respond to increases in plamsa Ca²+
examples of pathologies associated with abnormal signaling mechanisms
whooping cough: berdetella pertusis toxis blocks the inhibition of adenylyl cyclase
cholera (diarrhea): blocks enzyme activity of G proteins → cell continues making cAMP
examples of pathologies associated with abnormal signaling pathways
tight / occluding junctions: restrict the movement of the material between the cells
anchoring junctions: attach cell to each other (cadherins) or attach cell to matrix (integrins)
gap / communicating junctions: allow chemical & electrical signal to pass rapidly
what are the functions of the three types of cell junctions?
apoptosis
programmed cell death
necrosis
death from lack of oxygen / nutrients → affects surrounding cells
totipotent stem cells
have the potential to become any type in the adult body
pluripotent stem cells
have the potential to make any differentiated cell in the body
multipotent stem cells
undifferentiated cells in a tissue; can only differentiate into a limited number of cell types
exchange
transporting
ciliated
protective
secretory
what are the functional types of epithelial tissue?
produce movements & generate force
what are the functions of muscle tissue?
pass chemical & electrical signals from one part of the body to another
what is the function of nervous tissue?
structure
support
transport
physical barrier
what are the functions of connective tissue?
phospholipid bilayer
what are characteristics of the cell membrane?
tonicity
a physiological term used to describe a solution & how that solution would affect cell volume
isotonic solutions
two solutions containing the same amount of solute particles per unit volume
hypertonic solution
has a higher osmolarity than another solution
hypotonic solution
has a lower osmolarity than another solution
happy cells!
what is the effect of an isotonic solution on a cell?
crenation / shriveling
what is the effect of an hypertonic solution on a cell?
hemolysis / bursting
what is the effect of an hypotonic solution on a cell?
osmosis
the movement of water across a membrane in response to a solute concentration gradient
diffusion
the movement of molecules from an area of higher concentration of the molecules to an area of lower concentration of the molecules
280 - 300 mOsM / L
what is the normal range of osmolarity in the human body?
regulate the movement of ions
function of gated channel proteins
allow ions to move in & out across the membrane without regulation
function of open channel proteins
antiport carrier
moves molecules in opposite directions
symport carrier
moves molecules in the same direction
uniport carrier
moves only one kind of molecule
contransporters
move more than one kind of molecule
lipid solubility
molecular size
concentration gradient
membrane surface area
composition of lipid layer
what factors affect the rathe of diffusion through the cell membrane?
moves molecules across the concentration gradient
requires the input of energy (ATP)
produce a state of disequilibrium / make concentration gradients more pronouned
what are the characteristics of active transport?
clearance
volume of blood cleared of a substance per unit of time (an indirect measure)
phagocytosis: a cell engulfs a bacterium / other particle into a large vesicle (phagosome)
endocytosis
exocytosis: export large molecules, proteins synthesized in the cell, & wastes
what are the transport mechanisms for moving large molecules across the cell membrane?
sugars
amino acids
what are two molecules transported by facilitated diffusion?
paracellular transport
molecules pass through the junctions between adjacent cells
transcellular transport
molecules pass through epithelial cells — a combinations of active & passive transport
transcytosis
combines endocytosis vesicular transport across the cell & exocytosis; allows large proteins to move across an epithelium & remain intact
chemical disequilibrium: unequal concentration of solutes in two body compartments
electrical disequilibrium: electronegative ions in the ICF makes it a slightly negative environment compared to the ECF
what causes chemical & electrical disequilibrium in the body?
target cells / tissues
respond to electrical / chemical signals
gap junctions: direct cytoplasmic transfer of electrical and chemical signals between adjacent cells by membrane-spanning proteins (connexins)
contact-dependent signals: require interaction between membrane molecules of two cells; depend on CAMS
chemical signals diffusing through the ECF
autocrine signal: acts on the same cell that secreted it
paracrine: acts on cells in the immediate vicinity of the cell that secreted the signal
types of local communication
paracrine signals
act on cells in the immediate vicinity of the cell that secreted the signals
autocrine signals
act on the cells that secreted them
hormones
chemical signals that are secreted into the blood & distributed by circulation
neurotransmitters
a neurocrine signal that produces rapid effects
neuromodulators
a neurocrine signal that produces slow effects
receptor-channel: ligand binding → open / close channel
g protein-coupled receptor: ligand binding → opens ion channel or alters enzyme activity
catalytic receptors:
receptor-enzyme: ligand binding → activates intracellular enzymes
integrin receptor: ligand binding → alters enzymes or the cytoskeleton
what are the four categories of cell membrane receptors & their functions?
transducer
convert signals to amplifiers / responses
signal transduction
the process by which an extracellular signal molecule activates a membrane receptor to produce a specific response
nucleus & cytosol: directs a gene to “turn on” / synthesize mRNA
what are the locations / functions of intracellular receptors in the cell?
leukotrienes: constrict airways → role in asthma & anaphylaxis
prostanoids (prostaglandins & thromboxanes): sleep, inflammation, pain, fever
what is the effect of leukotrienes & prostanoids in the body?
block receptor activity
what is the effect of an antagonist ligand on a receptor?
activates the receptor similar to the primary ligand (competition)
what is the effect of an agonist ligand on a receptor?
simple endocrine reflex: release of insulin when blood glucose increases
simple neural reflex: knee jerk reflex
neuroendocrine reflex: release of breast milk in response to sucking
complex neuroendocrine reflexes:
insulin secretion in response to a signal from the brain
secretion of growth hormone
pattern of hormones released by the anterior pituitary
examples of neuronal, endocrine, & neuroendocrine reflexes
lipophillic
signals that are able to diffuse through the cell membrane
lipophobic
signals that are unable to diffuse through the cell membrane
internal failure of normal physiological processes
external sources: toxins, chemicals, bacteria, viruses, fungi
what are the origins of diseases affecting the human body?
law of mass balance
states that any gain must be equivalent to an equal loss
intake through the intestine / lungs / skin = excretion by the kidneys / liver / lungs / skin
metabolic production = metabolism to a new substance
what is the role of the law of mass balance in maintaining homeostasis?
neutral
the human body is electrically ___________ .
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