Human Physiology BIOL 2005 Midterm Notes:
The scientific method:
Over 200 cell types in the body:
4 Major Groups:
General Rule: Cells of a given type tend to cluster together = tissues.
Neurons: Use electrical signals as information
Muscle: composed of fiber cells, voluntary, unvoluntary movement
Both skeletal muscle and smooth muscle
Epithelial: Numerous cells make up this category.
Sheet like, continuous layers.
Found as surfaces and linings.
*Able to separate fluids from environments
Glands can be formed in E cells.
Exocrine vs. Endocrine (ducts vs. no ducts)
blood, bone, fat, etc.
provide physical support for other cells types
Extracellular Matrix: elastin, collagen, blood & lymph: connects various body parts, i.e.
Organs & Organ Systems:
Comprised of 2 or more tissue types
Perform particular functions (i.e. heart pumps blood)
The body as an External Environment
kept external by epithelial tissue – skin lining of lungs, kidney tubules, gastrointestinal tract.
The body as an Internal Environment
Extracellular fluid – exchanges materials with blood
Blood is contained in vessels lined with endothelium, no connection with external
Exchange points – lungs (O2 IN)(CO2 OUT)
Break down food, excrete salts etc.
Kidneys: filtration, selective transport, excess waste products removed (water, inorganic
salts, nutrients etc)
most abundant thing in the body (60%)
act as solvent, inorganic salts, ions, sugars, amino acids, proteins
Total Body Water (tbw) enclosed be outer epithelium. ICF and ECF.
cells in our bodies depend on each other, cells are sensitive to chance (must be regulated)
Keep conditions constant allows is to live in hot, cold, climates, elevation etc.
HOWEVER one organ system does not function to maintain homeostatic balance =
Disruption of homeosatsis can lead to disease, sickness = heat stroke, heat exhaustion
NEGATIVE FEEDBACK CONTROL SYSTEM ^^^^^^
POSITIVE FEEDBACK CONTROL SYSTEM vvvvvvv
response to stimulus in the same direction, not indefinetly, will terminate
eventually. Much less common, e.g. sneezing, child birth
Lecture 2 – Cells (Structure, function, metabolism)
Water as a solvent is very important to cell function (water molecules = polar)
molecules synthesized by living organisms
contain carbon atms (4 electrons valence shell)
4 types: carbs, lipids, proteins, nucleotides
major source of E in the body
C:H:O = 1:2:1 ratio
Polar molecules Hydroxyl groups (OH) and hydrogen’s (H)
3 sub categories: monosaccharide, disaccharides, and trisaccharides
Condensation: (dehydration synthesis)
hydrolysis, water molecules splitting up, water must be present to react.
C and H atoms, covalent bods
O is common too
Amphiphatic – contains polar and nonpolar regions
5 Classes of Lipids:
Proteins & Amino Acids ( P’s are polymers of AA’s)
Amino Acids simple organic compund containing a carboxyl group –COOH and an
Polypeptides polymers of amino acids, peptide bonds join 2 amino acids.
Secondary: alpha helixes, beta pleated sheets,
Tertiary: much more complex pH disrupts this shape
Quatiary: hemoglobin, 4 polypeptide chains.
Nucleotides & Nucleic Acids:
Function in energy transfer within cells
Form the genetic material of the cell
Nucleotide, 5 carbon carbohydrate, nitrogenous base, phosphate group
Found in nucleus, two nucleotides coiled into double helix
Bases: (A)(G)(C)(T) = CG 3H bond……….AT 2H bond
3’ carbohydrate end
5’ phosphate end
RNA: Found in cell nucleus and cell cytoplasm.
Cells can be membranous or not. Plasma membrane seperates cell from external
environment. Phospholipid Bilayer:
basic structure of membrane
can move laterally, side to side
cholesteral can be found within bilayer
barrier for large polar particles.
Integral, embedded within lipid bilayer dissociated only by physically disrupting
bilayer. Amphiphatic = polar and non polar regions.
Peripheral, loosely bound to membrane, can be dissociated from membrane
without disruption, most are found on the cytoskeleton.
Nucleus: main function transimission and expression of genetic material encoded in
Cytosol: gellike fluid, molecular composition, critical to cell function
Cell to Cell Adhesion:
Tight Junctions – common in epithelial tissue specialized for molecular transport.
Provides support so cells don’t tear apart under stress.
Gap Junctions: membrane proteins (connexions) bins 2 adjascent cells.
Cells in General: Function
metabolism and cellular transport
intercellular communication( release chemical messenger)
DNA contains “the code” for the creation of all proteins (only one strand = template
Triplets, the sequence of 3 bases = codon.
Regulation of Protein Synthesis: watch video*
Most proteins stick around for a long time,
Transcription: where rNA is synthesized using information from DNA.
• Membrane proteins: integral – found within the lipid bilayer, only dissociated by
• Peripheral Membrane Proteins: loosely bound to the membrane lipids or to
proteins, membrane carbohydrates: covalently bount to membrane lipids or
Organelles: Cell Division: Mitosis
=======cytokinesis (cytoplasm divides, cleavage, final stage)
Metabloic Reactions in the cell:
• Catabolic: breaking down large molecules to small ones, i.e. proteins –amino
acids, glycogen – glucose molecules
• Anabolic: larger molecules constructed from reactants i.e. amino acids – proteins,
• Metabolic Pathway: When the products of one reaction serve as the reactants of
another i.e. A – B – C – D
Types of Reactions:
Hydrolysis & Condensation
Hydrolysis – water reacts with molecules breaking down the bonds that link the
Condensation: joining two smaller molecules together, generating a water product.
Adding or removing a phosphate group
Oxidation reaction that removes electrons from an atom or molecule
Reduction – an atom of molecule gaining electrons
Energy Transfers in reactions:
Exergonic = proceed spontaneously in the forward direction
Endergonic = go forward only when energy is put into the process, may spontaneously go
in reverse if no energy is put in.
Reaction Rate Factors:
• Activation energy heights – rate of reaction increases as barrier height decreses
• Enzymes biomolecules that act as catalysts for chemical reactions
• Specificity: enzymesa are able to recognize and bind to specific substrates, some
can bind to a range of substrates, some are very specific
• Cofactors:Non protein components, allow enzymes to function
• Coenzymes: no catalytic activity, attatch to enzymes
Enzymes in reaction rates:
September 19 , 2013 – BIOL 2005
Summary of Lecture #3 – Chapter 4, Cell Membrane
Last time we covered:
• ‐ Chapter 2 and 3, cell structure and metabolism
• ‐ The makeup of the cells, chemical reactions within the cell, enzymes,
Introduction and brief announcements
‐ Guest lecturer, Dr. Jeff Dawson
General Concepts of the Chapter
• ‐ Transportation of material is also communication
• ‐ Why do cells need to communicate between each other?
Transport the need to move cargo |
Communicate ‐ > within ‐> Between
– Exported – Imported
‐> Detection – electrical gradients ‐ lipid signals
Transport: 2 primary Mechanisms
Passive Transport (Energy Independent)
• ‐ Simple diffusion
• ‐ Carrier mediated diffusion (facilitated diffusion)
• ‐ Ion Channels
Active Transport (Energy Dependent) • ‐ Primary
• ‐ Secondary
• ‐ The energy needed is already present Driving forces on molecules
• ‐ Kinetic Energy (Temp etc)
• ‐ Charge
• ‐ Concentration
Diffusion – chemical, electro chemical Ions – Carry +ve or –ve charge,
Chemicals – concentration matters
Note: 99% of the dry weight in the body is water, overall very few chemical
reactions going on in the body.
‐ Most important concept: Simply having the ions in the body is significant
van’t Hoff Equation (Pg. 95. Toolbox)
‐ Chemical driving force for an uncharged solute to move into a cell
Cl small molecule, can diffuse faster, can cause an excess of –ve charge in one
place under the right circumstances
Na larger than Cl , slower moving.
If the movement of Na+ is blocked within a system (membrane separating 2
areas) a charge difference can occur between the two areas (sides).
Blocking the movement of Cl , Na+ will be drawn to the Cl concentration. Similar
result. Nernst equation – Calculating the magnitude of the driving force (Pg. 99,
Toolbox) Ex. NaCl inside and outside the cell
• ‐ Driving force for Na+ to go into the cell
• ‐ Electrical difference is generated because of the difference
• ‐ Allows Na+ to be a “messenger”, fast acting.
Rapid electrical communication (chemical is much slower)
‐ Facilitates evolution to a ‘faster’ lifestyle, higher organisms
Na K pump
slow mechanism of transport
keeps electronic gradient across the membrane intact
Fick’s law and Equation (Pg. 103, Toolbox)
‐ accounting for net flux and size of concentration gradient
Flux = amount of material crossing a membrane of unit area/unit time. Movement
from one side to the other – probabilities dictate how much
Increasing surface area – maximizes the concentration gradient e.x . Fish gills,
Membrane bound structures
• ‐ fat soluble molecules can easily diffuse into cells through membrane
• ‐ Water can partially move past the membrane as it moves about
10 Minute Break
Membrane proteins themselves are affected by the lipids in the
membrane. • ‐ Carrier mediated diffusion (Glucose is one example)
• ‐ Glucose binds to a binding site
• ‐ Conformational change occurs
• ‐ Glucose moves from outside the cell to inside
• ‐ Glucose is released (substrate attraction, concentration or affinity
change may cause this)
• ‐ Glucose binding de‐stabilizes the protein to allow the conformational
change to occur.
Na ‐‐ Galactose, transporter
GLUT 4 – (Pg. 106, Focus on Diabetes box) ‐Transport membrane protein
‐ Not enough insulin, GLUT 4 is not expressed, glucose remains in the blood
stream 3D structure, top and side view slide
• ‐ If glucose concentration and flux rate is low
• ‐ Proteins become ‘busy’ concentration increases until leveling off,
occurred at this point.
• ‐ Rate of diffusion is maximized.
Approx 10,000/second – glucose molecules, membrane transport into the
Others – Pores in the membrane
Aquaporins – 13 classes, discovered in 1992. • ‐ Only transport water molecules
• ‐ Different roles for water in different tissues, thus different demand
Figure showing water molecules passing through the Aquaporin
• ‐ Protein structure has charged amino acids, matches water molecule
• ‐ Journal article – showing the ‘space filling’ figure of the molecules.
• ‐ This channel type does not bind anything to it.
• ‐ Pores do not bind
• ‐ Channels can bind
• ‐ Figure 4.12.
Slide from BIOL 3305 – a) Na+ channel pore b) K+ channel pore
‐ Water binds to ions, Na + H2O, can still fit through the channel ‐ Larger
molecules do not fit
To allow ions to pass through water must be stripped off.
K +H2O – K+ proteins remove water ‐ Conformational changes
Pore size selects for correct ions
Selectivity filter – allows specific ion+water to be processed
Some ion channels only open when certain conditions inside the cell are met.
e.g. voltage gated channels – nerve and muscle function
Primary Active Transport
Na+/K+ ATPase – best example of this Figure 4.14.
• ‐ Only Na+ inside to outside, K+ form outside to inside • ‐ ATP‐ covalent reaction, phosphate binds and protein structure flips, Na+
• ‐ Phosphate releases after K+ binds, K+ inside the cell
• ‐ Molecule doing the direct movement
• ‐ Piggy backs onto primary, moves molecules from low to high
Figure showing Lumen and model of water re‐absorption (Kidney)
‐ Transport processes can couple, just like reactions
‐ Glomerulus + nephron, blood circulates, waste accumulates
Only some ions are ‘recognized’ by the body. Certain ions and molecules
Adaptive reasons for this‐ why?
Kidney increases surface area
‐ Pumps pull Na out of the cells, Na can then flow back in from the lumen,
recovering Na from the waste product of the body
Na+ can also be co‐transported into the cell. With: Glucose, Cl , Vitamins,
When Na is constantly pumped out, K keeps being pumped in
‐ Leaky K+ channels allow it to leak out again ‐ Cycle continues
K is not co‐transported – unknown why selection for K did not occur.
Osmosis ‐ Diffusion
‐ Flow of water across a membrane down its concentration gradient
Sugar can draw water out of fruit (strawberry example). Figure 4.20
‐ Osmolarity #s and changes 1° ‐ glucose 0.1 mol/l = 0.1 osmol
2° ‐ NaCl o.1 mol/l = 0.2 osmol
Water amount is inversely proportional to ions
Pressure can counter diffusion from osmotic pressure
Increase pressure of a system will decrease diffusion potential
Reverse Osmosis systems work this way – pure water out
Tonicity ‐ solutions
Hypotonic – causes cells to swell Hypertonic – cells shrink
Remaining Ch 4 material – will briefly be covered in Lecture #4
‐ Movement of molecules across 2 membranes ‐ Trancystosis
Readings for this Lecture
‐ All of Chapter 4 is relevant, please read.
Lecture 4: Sept. 26 th
Phagocytosis: Cell “eating” the plasma membrane engulfs a particle, which is then
broken down by lysosomes.
Pinocytosis: Cell “drinking” the plasma membrane engulfs small particle solutes and
filters them in.
Receptor Mediated Endocytosis: endosomes carry material into the cell with them.
Carrying Material Out of the cell: Exocytosis
A vesicle from inside the cell fuses with the plasma membrane and realeases particles on
the out side. (3 functions too = adds compartments to the membrane, recycles receptors, and excretes substances to the extracellular fluid).
Epithelial Tissue is the barrier between internal and external environments.
Absorption = into the cell
Secretion = out of the cell
Movement across 2 Membranes:
solute transport = Na+ K + pump
water transport = osmosis
transcytosis = endocytosis and exocytosis
Cystic Fibrosis: affects the respiratory tract, thick mucus build up affects breathing
ability. Normally watery fluid is able to dilute the mucus.
Water osmosis follows solute transport. – problem with Cl transport, i.e. water transport
has no path to travel to dilute mucus.
Chapter 5 – Chemical Messengers:
3 Categories of Chemical messengers:
Paracrines: secretions released from/to adjascent endocrine cells.
Neurotransmitters: chemicals (neurotrines) released into interstitual fluid by neurons
Hormones: released from endocrine glands into interstitual fluid, travel via blood flow.
Chemical Messengers to know:
Acetylcholine: a neurotransmitter that triggers the control of skeletal muscle
Amino Acids 4 acting as nuerotransmitters, synthesized within the neuron that will secrete them (glutamate, aspartate, glycine, gammaaminobutyric
AminesDerived from amino acids, synthesized in the secretory cell except
Peptides & Proteins: cytosolic mRNA is template, codes for amino acid
Steroids: cholesterol processed in series of reactions, in smooth ER or
Eicosanoids: similar to steroids (immediate release) Enzyme catalyzes release
of arachidonic acid from membrane phospholipids
dissolved blood (must be hydrophilic)ccccccccfffcfccdrt5
bound to carrier proteins in the blood
Chemical Messengers need to bind to target cells in the nucleus.
Intracellular: lipophillic (cytosol or nucleus of target cell), alters protein synthesis
Membrane bound, lipophobic: 3 categories:
Channel linked: fast and slow, ion movement
Enzymelinked: act as enzyme and receptor
Gproteinlinked: activated Gproteins in PM, g proteins act on effectors (ion
channels and enzymes)
Signal Amplification and Long Distance:
SA: relies on second messengers to produce a greater response from target cells when
only a small concentration are present.
Longdistance: endocrine and nervous system perform these tasks
The Endocrine System:
Primary organs: function to secrete hormones is first function, some in the
brain, most outside the nervous system: Hypothalamus and pituitary gland =
together regulate almost all body systems. Pituitary gland= anterior and
E.g. Antidiuretic Hornome (ADH) when concentraion in plasma solute is
high, target cells in the kidneys pick up on this and the hypothalamus
synthesizes neurons to increase water absorption (treat dehydration). More
e.g.s adreanal glands and pancreas.
Secondary organs: secretion of hormone is secondary to other functions, many
organs form other systems too. i.e.
Pineal gland, thymus, thyroid, parathyroid, adrenal glands, pancreas
Adrenal Gland: Gonads, testicles and ovaries:
Secrete various hormones, testosterone, progesterone, etc
Heart, liver, kidneys, skin….all help to maintain the body, heal, growth.
Secretion of Hormones:
Hyposecretion: too little hormone secreted (think diabetes, not enough insulin)
Hypersectretion: too much hormone secreted
E.g. Acromegaly – hormone released to age too quickly….think picture of the lady at
Whole Body Metabolism:
We eat food for energy.
Endocrine system controls whether we use or store that. Food intake is intermittent, food
is stored and then broken down between meals.
Glucose levels must be maintained at all times to ensure brain function.
Body temperature regulation = hypothalamus regulated.
Growth Regulation = Growth hormone (GH)
Factors that affect GH:
anterior pituitary secretion of (growth releasing hormone, growth inhibiting
GH increase bone strength, circumference and length.
Osteoblasts: lay down new tissue on outer bone surface.
Osteoclasts: reabsorption of bone at inner surface.
Produce cartiladge, elongate bone, usually stops after adolescence.
enzymes & iodide are required to synthesize TH (thyroid hormone)
Primary action = raises bodies basal metabolic rate
Glucocortoids, maintain concentration of enzymes able to break down
proteins, fats and glycogen
Cortisol = the hormone for stress, helps the body adapt, blood flow to brain
Human physiology October 3rd 2013
Nerve Cells, Signaling, Synaptic Transmission, and Integration
(Chapter 7 & 8)
CNS & PNS
Central Nervous System:
• Composed of Brain and Spinal Cord
Processing of signals from the PNS. (all input information is processed here) And then
sent out to certain organs. As well, it is the site of learning, memory, emotions, thoughts,
language, and complex functioning
Peripheral Nervous System:
• Afferent (Receive): Somatic, special, visceral (process info from organs and send
• Efferent (Send): somatic & parasympathetic (transmit info from CNS to effector
organs) Somatic: volunrary (skeletal muscle contraction)
Autonomic: involuntary (sweat glands, blood vessels) Further divided into:
Enteric Nervous System – neurons in gastrointestinal tract, independent function but
communicated with autonomic.
The Nervous System: Cells
Neurons: smallest functional unit of the nervous system (composed of cell body,
dendrites, axon) *As adults we have all the neurons well ever get.
Stem cells – present in the brain, can differentiate into neurons (Can replace Neurons!!
Dendrites – branches, receive input from other neurons at synapses
Synapses – branch patterns vary per neuron type.
Axon – nerve fiber, sends info, 1mm 1m in length – can be branched, variable per cell
type Presynaptic neuron – one sending the signal
Postsynaptic neuron – receiving the signal
Signal Transport: Anterograde – moving from cell body to axon terminal
Retrograde – moving from axon terminal to cell body
Specialized Functions of Neurons:
ability to alter ion permeability on the PM (to alter electrical properties)
Leak Channels – nongated, always open create resting membrane potential
Ligandgated Channel – open or close in response to chemical binding to a receptor in the
Voltagegated channels – open or close in response to change in membrane potential.
Mechanically –gated channel
Structural Differences in Neurons: (3 main types)
Bipolar – cell body is in the middle of the neuron with dendrites on both sides
Pseudounipolar – one axon with one peripheral and one central dendrite
Multipolar – multiple projections from the cell body (1 axon +dendrites)
CNS organization: cell bodies group and form nuclei, axons and dendrites grouped as
PNS organization: cell bodies group to form ganglia (outside of the central nervous
system) axons bundle to form nerves
Internuerons – in CNS, 99% of all neurons in the body involved in all processe of the
Glial “glue” cells – 90% of the cells in the nervous system (support for neurons, by
supporting structure and metabolically)
4 Types of Glial Cells:
astrocytes, microglia, oligodendrocytes, Schwann cells
Myelin – insulating layer from oligodendrrocytes (many cells coated) and Schwann cells
(only one cell coated). Nodes of Ranvier – gaps within myelin
Axonal membrane contains VGNa+ and K+ channels
transmission of AP by allowing ion movement across the membrane
Ohm’s Law = I = E/R
KNOW THE TERMS, MULTIPLE CHOICE Q’s********
Table 7.1!!!!! (action potential, equilibrium potential, etc)
The Nervous System – Membrane Potential
Resting Membrane Potential (RMP)
in neurons, around 70mV
more negative inside than outside the cell
Na+ is higher concentration outside the cell (balanced by Cl outside the cell)
K+ is higher concentration inside the cells(A, primarily proteins)
Neurons are permeable to both Na and K
There are more open K+ channels than Na+ (approx 25x)
Ions travel in the direction of driving force
Due to permeability differnce, net outward movement of +ve charge results ina negative
When ion flow = all equal, no net movement of positive charges move in or out of
Resting = 70mV
K+= 94mV Gated channels, alter membrane permeability when they open or close, affect ion
movement across the membrane (voltagegated, ligandgated, and mechanically gated)
Graded potentials – small electrical signals, in a short range, occur when the ion
channels within the membrane are open(aka stimulated) Magnitude of Stimulus is in
relativity to the strength of the graded potential. They degrade overtime, dissipates.
Action potentials occur when graded potential is depolarized juuuuuuuust enough to
Excitatoy membrane potential change towards the threshold
Inhibitoy membrane potntial change away from the threshold
Summation important for AP initiation (can build off eachother and add up to reach
AP will propogate over a long distance (axon) without losing their strength (add up),
makes then very good communication signals! (good travellers)
In the neuron, 3 phases:
Ion Channels –voltage Gated (Na+ & K+)
Primarily found in PM of axon hillock and axon
myelinated: concentrated more in the nodes of ranvier
unmyelinated: evenly distributed along the axon
2 Types of Gates:
Closed and capable of opening: inactivation gate =open, activation gate =closed,
depolarizing stimulus can open
Open, both gates open, Na moves through, depolarization phase. Na+ gate opening is a positive feedback system, Na channels open, Na moves through,
triggering more Na channels to open etc.
AP threshold level is the same one required to initiate the regenerative opening of the
K+ voltagegated channels:
single gate, slower response
Positive charge movemnt out o f the cell repolarizes it
Part of negative feedback loop
All or None Principle:
AP’s commence once threshold is achieved, no aprtialAps occur , the amplitude of the AP
is the same (not graded).
Action potential will therefore always act to its fullest.(always the same)
Refactory Period: (neurology) the time after a neuron fires or a muscle fiber contracts
during which a stimulus will not evoke a response.)(approx 515ms)
The time frame of reduced excitability divided into 2 phases: absolute and relative
Ap’s propogation down the axon to the axon terminal without decrement.
Electronic conduction allows current to dlow to adjascent areas from the stimulus area.
(resting – propogation)
Distance where initial change in voltage has decayed to (37%) of its value. A measure of
how far the axon current can flow before leaking out of the axon.
Depends on resistance to current flow.
The greater the membrane resistance
Diameter affects axial resistance. Myelinated (from Glial cell) Axons: an insulation support functioning to cover and
protect the axon.
Lecture 6 – CNS and Sensory Systems
Glial Cells Cont’d:
We covered 2/4 Glial Cells in last chapter (Schwann, and Ocygloceryotes)
star like formation
Form tight junctions between endothelial cells
Patch and cover axons (can cover many)
Protect neurons from toxic substances etc.
active immune defence!
Protect the CNS via phagacytocis
Patrol the brain! J
BloodBrain barrier, makes it difficult for infections to easily reach vulnerable parts of
the brain, seperates the brain blood flow from other parts of the body (tight junctions)
Physical Support: Meninges: 3 tissue layers
Cerebrospinal fluid: shock absorption
Dura Mator: Closest to the bone, outermost, tough
Archanoid Mator: middle layer, weblike appearance
Pia Mator: innermost layer adjascent to nerve tissue
The CNS Blood Supply:
15% blood pumped from heart goes to CNS
20% of all consumed oxygen is by the brain
50% of all consumed glucose goes to the brain
Matter Makeup of the CNS:
Grey Matter & White Matter:
Spinal Cord Matter Makeup:
White matter on the outside, grey matter on the inside.
Spinal Cord makeup:
*coccygeal nerve (1)
Grey Matter = dendrites, cell body
White Matter = Axons/ myelination
Dorsal Horn: dorsal side horns
Ventral Horn: ventral side horns
Lateral Horn: in between dorsal and ventral
White matter has ascending and descending tracts that communicate between various
levels of spinal cord and the brain.
3 major parts: brainstem, cerebellum, Forebrain:
diencephalon(thalamus, hypothalamus, pituitary gland (tiny), pons, medulla
Brainstem: spinal cord
Parietal Lobe: sensory, touch, temp, itch, pain
Frontal Lobe: Motor cortex = language, personality, choices
Ocipital Love: Process visual information
Temperal Lobe: Hearing Functions
Language: 2 area’s:
Broca’s area: express language, ie. Speak
Wernicke’s area: ability to understand language
Learning & Memory:
2 different of Learning types:
Associative: connections between 2 or more stimuli made
Nonassociative: the repetition of a single stimuli
Memory 2 types:
Procedural: skills and experiences ie. How to ride a bike
Declarative: facts and knowledge
VISION: 3 layers of photoreceptors in the eyes:
inner layer(ganglion cells), middle layer( modulators), outer layer(rode &
HEARING: Sensory Systems:
Chemoreceptors in the mouth respond to the chemicals in food.
Signal transduction: sweet, sour, bitter, salty…
Proteins on the receptor cells on the tongue signal the release of Ca+, engage gate
Olfaction: the organ responsible for smell, located at the base of the nasal cavity.
Lecture 7 – The Autonomic & Somatic Nervous System/ Review Lecture
October, 17 2013
Chapter 11 – Efferent Nervous system:
• Autonomic NS: innervations of most effector organs and tissues (broad)
Functions occur at subconscious level
Also known as the “involuntary” nervous system
Primary Function: maintain homeostasis, maintain the bodies operations. Maintain the balance inside the body.
Dual Innervation: 2 more branches within the autonomic nervous system are:
Sympathetic and parasympathetic systems, both innervate most organs, effects are
diametrically opposed to each other.
Parasympathetic: “rest & digest”
resting conditions, simulating digestive organs, inhibiting cardiovascular system.
Sympathetic: “:fight or flight”
Excitation, active periods, heart rate, force increase, blood flow shift and energy
Two Types of neurons arranged in these series:
Preganglionic neurons – from CNS to autonomic ganglia
Postganglionic neurons – from autonomic ganglia to effectors organs
Neurons can synapse to more than one other neuron at a time.
Pregangliac neurons emerge from the lumbar and thoracic spinal regions,
Arranged in 3 possible patterns:
First: MOST COMMON: short axon from lateral horn > spinal nerve, branches off and
synapses in ganglia.
Second: Long pregangliac neurons innervate endocrine tissure (wide spread sympathetic)
Third: pregangliac neurons synapse with postgangliac neurons (in pairs, celiac ganglia –
stomach, liver, spleen) – Inferior(lg.intestine, kidney, bladder) & superior (sm. Intestsine,
upper lg. intenstine)
Parasympathetic NS – Anatomy:
Neurons originate from the brainstem/sacral spinal cord
Pregangliac neurons are long, terminate near organ
cranial nerves: vagus nerve, oculomotor nerve, facial nerve, glossopharyngeal nerve
Contrast form sympathetic: preganglionic neurons originating form the spinal cord do not
join with the spinal nerve.
Autonomic Neurotransmitters and Receptors:
Neurotransmitter: 2 Primary: acetylcholine and norepinephrine.
Two types of Neurons within these systems:
release acetylcholine, pregangliac neurons of sympathetic and parasympathetic
Release norepineprhine, almost all sympathetic postgangliac neurons
Both types of neurotransmitters can bind to different classes and subclasses of cholinergic
and adrenergic receptors, respectively. Cholinergic:
Nicotinic: 4 subclasses:
Cell bodies and dendrites of sympathetic and parasympathetic ganglionic neurons
Chromafin cells and skeletal muscles.
Cation channels, depolarization of postsynaptic cell
5 Subclasses, effector organs of parasympathetic nervous system
G protein coupled, excitatory or inhibitory
Autonomic Neurotransmiters and Receptors
2 Major Classes:
ineffector organs of sympathetic nervous system
-alpha and beta
coupled to G protein, activating or inhibiting second messenger systems
a receptors have greater sffinity for epinephrine, inhibitory response
B1, B3 receptors have equal affinities for norepinephrine and epinephrine, mostly
Autonomic Nervous System:
-a synapse between an efferent nrueon and effector organ
-a synapse between postganglionic neurons and effector organs do not have
discrete axon terminals
-neruotransmitters released from varicosities
Visceral reflexes – autonomic changes in the functions of your organs in
response to internal body conditions. E.g. Reflex arc of standing up.(when u
stand up a change of blood pressure occurs…why you get a little light headed
when you stand up too fast)
Regulation of Function – BrainAreas
Hypothalamus: Fight or flight, sympathetic activation, body temp.
food intake, H2O Balance.
Pons and Medulla Oblongata: respiratory and cardiovascular
regulatory centers present. E.g. heart blood vessles, smoth muscle
of respiratory airways
Nausea, sweating, difficulty standing upright
Caused by a mismatch or sensory inputs
-vestibular apparatus visual system
propriocepters throughout the body. BOTH branches of the autonomic NS.
Scopolamine – muscarinic cholinergic antagonist can counteract motion sickness. (drug
Somatic Nervous System
-controls the skeletal Muscles
-only one single type of efferent neuron – Motor neurons
-the voluntary Nervous System
Single motor neuron travels from the CNS to skeletal muscle where it innervates.
(only one signal per muscle fiber cell)
a single motor unit = neuron and fiber cells it innervates.
-the region where the branch of the motor neuron synapse at a skeletal muscle fiber
-axon terminals are called terminal boutons( store and release acetylcholine)
Motor endplate: opppostie to terminal boutons in PM of muscle fiber. Contains nicotinic
cholinergic receptors within invaginations
These “Junctions” are vulnerable and a termed “target sites” to animals that inject venom.
Latroxin- black widow spider, causes muscle spasms = respiratory failure
Crotoxin- in rattlesnakes, paralysis of skeletal muscles = no contractions
Curare: -paralyzing effects on skeletal muscle posin used on dart tips used in blow guns.
Blocks communication at neuromuscular junction, binds to the nicotinic cholinergic
receptors, skeletal muscles do not receive signal to contract
CLINICAL USES TODAY:
Dialation of the throat, rectum
Spastic paralysis relief
Midterm Review: (Chapters 1-11, 21)
80% Multiple Choice (definition oriented)
5-10% matching terms/fill in the blank
5-10% labeling a diagram:
Focus on: Epithelial/membrane structure layout,
Major areas of the brain (lobes etc.)
Neurons/structure/of diff types (axonal transport microtubules)
Cell structures/ organelles, membranes, etc. Sensory structures/eyes (3 layers of the retina, lens etc.) & ears
layout (inner outer ears)
Some nasal anatomy (mucus glands, structures)
Spinal Column (anatomy/later, dorsal horns etc.)
“compare and contrast x vs. y”Alternating proceses –e.g.
sympathetic and parasympathetic neurons.
Procces q’s, signal Na+ K+,, excocytosis.
Cell membrane transport
References to clinical uses, functionalities etc.
Epithelial Membrane/ Structure Layout:
Made up of connective and epithelial tissue, these serve as lining coverings for various
No Lecture 8
Lecture 9 – Chapter 12, 13
Muscular Physiology and Cardiovascular system:
Final exam: 21 December 7pm (35%)
The somatic nervous system innervates skeletal muscle
The autonomic nervous system innervates smooth muscle, cardiac muscle
Q: How are the action potentials here different from what we learned about in neurons??
A: muscle contraction = physical contraction = end point
Rather than a chain reaction of signals flowing through synaptic cells “excitable”
Muscle Cells: high energy cells = lots of ATP
Anaerobic glycolysis = how they get there E
Skeletal Muscle: formed during embryonic development connected to at least 3 bones
biceps, triceps, gastrocnemious etc.
tendons connect muscle to bone
EXCEPTIONS: those connecting to skin, cartilage, facial muscles,
connecting to larynx etc.
Muscles consist of:
The body : “meaty” force generating component
Epimysium: surrounding connective tissue, holds muscle fibers together
Perimysium divides muscles into “bundles”
Muscle fibers aka cells, run the length of the muscle (fused cells