(1) homeostasis and cell physiology student
TRANSCRIPT
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1) Organization - multicellular
2) Responsiveness
3) Growth - cell number, size, or amount of substances
(nutrients/fat deposition)4) Development and differentiation - shift fromgeneralized cells to specialized cells
5) Reproduction
6) Metabolism andExcretion (rid of waste products)
The Basic Functions of
Organisms
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Anatomy
Greek:
-ana (apart)
-tome (to cut/dissection)
The study of the structure of a livingorganism
Without knowledge of the anatomy of the body andcell structure, this course will be much more
difficult
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Gross Anatomy
Surface anatomy
Regional anatomy Systemic anatomy
Developmental anatomy
Microscopic anatomy
Cytology
Histology
The Specialties of Anatomy
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Anatomical Variation
No two humans are exactly alike 70% most common structure
30% anatomically variant
variable number of organs
missing muscles, extra vertebrae, renal arteries
variation in organ locations
situs solitus
situs inversus (things are flipped)
dextrocardia
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Physiology
The branch of knowledge which studies howstructures of a living organismfunction in order
to maintain life
function is an aspect ofstructure
Function is the how and whyof the system orevent
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Approaches to Physiology
Teleological approach
Is thinking about the why
Why do RBCs transport oxygen?
because cells need oxygen and RBCs bring it to them
Mechanistic approach
Thinking about physiological processes are
the how How do RBCs transport oxygen?
Oxygen binds to hemoglobin molecules contained in
RBCs
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Cell physiology
Special physiology
( e.g. cardio physiology )
Systemic physiology
(e.g. cardiovascularPhysiology)
Pathological physiology
The Specialties of Physiology
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Physiological Variation
Sex, age, diet, weight, physical activity
Typical physiological values
reference male 22 years old, 154 lbs, light physical activity
consumes 2800 kcal/day
reference female
same as male except 128 lbs and 2000kcal/day
Overmedication of eldery
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Organ systems
Systems ( 11 )
Integumentary, Nervous, Skeletal, Endocrine,
Muscular, Cardiovascular, Lymphatic, Urinary,Respiratory, Digestive, Reproductive
Organs
Heart, lung, pancreas, stomach, brain,etc.
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Chemical Molecules: Complex proteins comprised of atoms (DNA) Atoms
Cellular Comprised of many macromolecular complexes
The most basic functional unit of any multicellular organism Tissues
Comprised of various cell types Connective, muscle, nervous, epithelium
Organ Contain various tissue types
Organ systems Cardiovascular, respiratory, integumentary, etc.
Organism Homo sapiens
Organization of the Human
Body
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Levels of
Organization
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Homeostasis
The process of maintaining a relatively constant internalenvironment within an organism
(body temperature, heart rate , blood glucose levels, etc..)
Time
Normal
Range
Loss of homeostatic control
Set
Point
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Equilibrium
A state of rest or equalbalance All biologic phenomena act to adjust: there are no
biologic actions other than adjustments. Adjustment isanother name for equilibrium. Equilibrium is the
universal, or that which has nothing external to derangeit. Charles Fort
Homeostasis does not mean equilibrium whenconcerned with the entire body
i.e. the ECF and ICF usually exist in a state thatmight be best called adynamic disequilibrium
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Most cells are
in contact with
the ECF
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Homeostasis and Controls External or internal
Physiological attempt tocorrect occurs sensors detect
Integrating center process Response of cells and organs
occur
Successful compensation homeostasis reestablished
Failure to compensate Pathophysiology
illness/disease
death
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Mechanisms which maintain
systemclose to set point
Autoregulation (intrinsic regulation)
constant blood flow regardless of BP
Ex: renal system Extrinsic regulation - thermoregulation
(behavioral)
Mechanisms for Homeostasis
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A receptor ( input
signal)
A control center
An effector (output/efferent signal)
Homeostatic regulation
involves
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Homeostasis is mediated by the
Tonic
Activity
Control center
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Negative Feedback
Primarymechanismfor homeostasis!
Response
Decrease
stimulus
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Negative Feedback: The Control of Body
Temperature
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NOT homeostaticequilibrium, but instead
an Unstable equilibrium
Response
More
stimulus
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Positive Feedback: Blood Clotting
Positive feedback control- mechanisms which drive systems
farther from set point
usually leads away from homeostasis and can result in death
e.g. uterine contractions during childbirth
orgasm
blood clotting
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Harmful Positive Feedback Loop
Fever >140 degrees F metabolic rate increases
body produces heat even faster
body temperature continues to rise further increasing metabolic rate
Cycle continues to reinforce itself
Becomes fatal at 113 degrees F Damage to brain occurs around 107
degrees F
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Homeostatic Control
Body predicts that a change is about to occur and
starts the response in of the change
e.g. salivation
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3-25
Cytology scientific study of cells began when Robert Hooke coined the word,
cellulae to describe empty cell walls of cork
Theodore Schwannconcluded, about two
centuries later, that all animal tissues aremade of cells
Louis Pasteur established beyond anyreasonable doubt thatcells arise only fromother cells refuting the idea of spontaneous generation
living things arise from non-living matter
Modern Cell Theory emerges from this
Development of the Cell Theory
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1) Cells are the building blocks of all plants and
animals
2) Cells are produced by the division of pre-
existing cells3) Cells are thesmallest units that perform all
vital physiological functions
4) Each cell maintains homeostasis at thecellular level
The Cell Theory
- Homeostasis at higher levels reflects combined,
coordinated action of many cells
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The Cell
Rough ER
Secretory
vesicles
Microvilli
Smooth
ER
Golgi
apparatus
NucleusCytoskeleton
Cell membrane
Mitochondrion
Cytoplasm
Ciliacilia
cytoplasm
mitochondria
Rough ER
nucleus
Cell membrane
microvilli
Please review the function of organelles in Fig 3.4
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Is surrounded by extracellular fluid,
which is the interstitial fluid of the
tissue
Has an outer boundary called the
cell membrane, plasma membrane, or
plasmalemma
A typical cell
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Where does most physiology occur?
Cell membrane
Cell membrane composition Lipids
phospholipid bilayer
Cholesterol
Carbohydrates (sugars)
Proteins
Cell Membrane
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Cell membrane
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Cell membrane functions1.Forms physical boundary of the cell
2. Selectively permeableregulates transport across the
membrane
3. Structural support
4. Motilityfacilitated by the presence of cilia (moves EC
fluid, flagellum (moves cell), etc.
5. Signal Transduction- movement of a stimulus from oneform to another
6.Cellular recognition- autoimmune conditions
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Components of the plasma
membrane
1) Lipids - not very soluble in H20 Fats and oils
Phospholipids
Phosopholipid bilayer contains: Hydrophillic , polar head
Hydrophobic, non-polar tail
Glycerol + Phosphate group
Fluid mosaic modelphospholipids swim aboutthe bilayers of the cell membrane
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choline
PO4-
glycerol
Head
Polar
Hydrophilic(water-loving)
Tail Non-polar
Hydrophobic(water-repelling)
Phospholipid Molecule
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Components of the plasma
membrane
1) Lipids
Phospholipid bilayer
Cholesterol and other lipids
Glycolipidssugar attached to a fay
Lipoproteins- (HDL and LDL)
Steroids
These all influences membrane fluidity
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Structure of phospholipids and glycolipids
C,H,O
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Glycolipids
Carbohydrate-attached lipids.
Function:
Provide energy
Serve as markers for marker for cellular
recognition (markers that can tell if a cell
belongs or not)
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Components of the plasma
membrane
1) Lipids
2) Carbohydrates- most abundant biomolecules,yet only 5% of the membrane
Glycoproteins
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Membrane components:
carbohydrates
Carbohydrates
Simple sugars
fructose,glucose , galactose (monosaccharides or oligosaccarides)
Sucrose, maltose, lactose (disaccharides)
Complex sugars chitin, glycogen,cellulose , starch, dextrin (polysaccharides -
high in energy)
Membrane carbohydrates form the Glycocalyx
Glycocalyx (sugar coat on the outside of the cell)- located on
extracellular surface
Sperm have a sweet tooth
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Function:
orient andanchor membrane proteins
serve as a type of recognition particles
ABO bloodgroups determined by
oligosaccharides on surface of RBC
(antigens)
Glycoproteins
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Components of the plasma
membrane1) Lipids
2) Carbohydrates
3) Proteins (at least50% of membrane) What are proteins?
Proteins are a linear chain of amino acids
Primary structure (amino acids sequence)
Secondary structure (amino acid interactions)
Tertiary structure (complex forming) Quaternary structure (protein complexes)
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Primary structure (amino acids
sequence)
Secondary structure (amino acid
Tertiary structure
structure (protein
complexes)
Four levels of protein structure
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1) Integral proteins
2) Peripheralproteins
3) Anchoring/structureal proteins
4) Enzymatic proteins5) Receptor proteins
6) Carrier proteins
7) Channelsa) Non-gated Ion
b) Gated
Membrane protein classes
include:
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Membrane Proteins
1) Integral membrane protein
normally spans membrane - transmembrane protein
Crosses the membrane
2) Peripheral membrane protein
- bound to the inner or outer surface (two com together tomake tight junctions
3) Anchoring proteins (junction proteins)
attach cell membrane tostructures : cytoskeleton
attach cell membrane to other membranes: intercalated discs
These proteins can degrade when metabolized
4) Enzymatic Proteins (help break down other substances)- Binds enzymes to catalyze intracellular or extracellular reactions
Example: peptidases
M b i
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Membrane proteins5) Receptor proteins
Bind to ligands , causes cells to respond
Ex: Insulin, antigen, glucose, neurotransmitters, serotonin,epinephrine, ect.
6) Carrier proteinstransport solutes across membranes
- Includes uniport, symport, andantiport
ATP dependent - Na+ K- exchange protein
ATP independent- neurotransmitter transporters
NEVER FORMS AND OPEN CHANNEL7a) Non gated ion channel proteins
Non-gated- always open Leak Channel or pores (Cl- channel, K+ channel, etc.)
Selectivity determined by channel diameter and electrical
charge of amino acids
7b) Gated ion channels
gated = opening/closing
gated by voltage change (Na+, K+, Ca2+ channels)
gated by chemical ligand (chemical binds to receptor) (acetylcholine
receptor)
gated by physical change (physical distortion of membrane) ( temperature,
force)
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Channel Protein Structure
Selectivity is determined by channel
of amino acids that line the channel
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Types of gating:
Gated Channel Proteins