Key ConceptsFunction Vs. Process• Function why does a system exist, its purpose,

what is does for the organism (teleological approach)

• Process How does a system perform its function, (mechanistic approach)

PHYSIOLOGY integrates both approaches to understand “How” physiological systems work, and “Why” they are there

Key Concepts

• Homeostasis Maintaining the internal environment of an organism relatively stable by maintaining certain properties within a normal range

• E.g. Temperature, blood glucose, blood pressure, salt concentrations, pH

35

35.5

36

36.5

37

37.5

38

38.5

Homeostasis

• Keeping these parameters around a set point requires constant monitoring, compensation, and energy input. E.g. Like driving a car straight requires many corrections with the steering wheel

• Additionally set points may change, either due to biological rhythms or in response to environmental change

Tissue TypesTissue Types Found in Body

Epithelial-Protection and nutrient/waste exchange

Exchange- Rapid material exchangeTransporting- Selective material transportCiliated- Airway and reproductive tract (help move stuff)Protective-Skin, protects from environmentSecretory- Synthesize and export products into extracellular environment

Connective-Structural support & barrier

Loose – elastic tissue (return structures to prior form)Dense – Provide strengthAdipose – adipocytes Blood – Watery matrixSupporting – Cartilage and bone structural

Muscle- Contract to produce force/movement

SkeletalSmoothCardiac

Neural- transmit information

NeuronsGlial

Cell to Cell CommunicationType DescriptionGap Junctions

-Connexons (bridge structure composed of proteins called “connexins”) join interior environments of adjacent cells-Can transmit electrical and chemical signals-Can open and close

Contact-Dependant Signal

-Interaction between membrane molecules on two cells-Membrane proteins can than activate a signal upon binding-Found in Immune cells and during development (neurons growing cell extensions from nervous system to distal parts of body)

Add Red Dye to left cell

Connexon

Cell to Cell CommunicationType DescriptionLocal Communication

-Communication between neighbouring cells using paracrine hormones as signalling molecules-Autocrine signalling is local communication where the cell that produces the molecule also receives it-Example of histamine vasodilator secreted by damaged cells which causes surrounding capillary cells to be more permeable to fluid (swelling) and white blood cells/antibodies

Long-Distance Communication

Nervous and endocrine system-Similar to paracrine hormone secretion, except signalling molecules travel large distances to target (hormone through blood stream or electrical signal down entire length of neuron)-Target cell needs receptor

Cell

Target Cell

Paracrine

Autocrine

Blood

Endocrine

Receptors

• Signalling specificity depends on Receptor Proteins• Signalling molecule binds onto a specific receptor

found only on target cells transmembrane, cytosolic, or nuclear location

• Receptor protein is what brings about the response to signal

• Agonists Binds receptor and activates response• Antagonists Binds receptor and produces no

response (inhibitory activity)

ReceptorsBiological Signalling Molecule

Foreign “drug” molecule

Foreign “drug” molecule

Normal Signal Pathway With Response

Agonist Pathway With Response

Antagonist Pathway Without Response

Nervous System

• 1) Receives information Sensory neurons from external environment (light, sound, pressure etc)

• 2)Integrates Information Organizes new information, combines with stored information

• 3) Transmits Information Sends signals to muscles/glands to carry out action

Neurons

Ref: Wikipediahttp://en.wikipedia.org/wiki/File:Neuron_Hand-tuned.svg

Dendrites

Nucleus

Soma

Myelin Sheath/ Schwann Cell

Node of Ranvier

Axon

Axon Terminal

NeuronsComponent Description

Soma Nucleus & biosynthetic machinery (ribosomes protein synthesis)Helps keep cell Alive

Dendrite Receive information (from sensory cells, or other neurons)•Can be part of synapse (post synaptic)

Axon Cytoplasmic extension that sends out information (to other neurons/muscles/glands)

Axon Terminal Connection between neuron/other cells•Can be part of synapse (pre synaptic)

NeuronsStructure Description

Pseudounipolar Somatic Sensory neuron-Axons and dendrites joined together as one long process

Bipolar Smell/vision Sensory neurons-Single axon & dendrite

Anaxonic No (apparent) axon-Interneurons

Multipolar-CNS Highly branched w/ short extensions

Multipolar-Efferent 5-7 dendrites, 1 Long axon

Nervous SystemComponents Central Nervous System Peripheral Nervous SystemMajor Structures •Brain

•Spinal Cord•Everything else•Connects brain/spinal cords to muscles/organs•Receptor CELLS (convert stimuli to electrical signals)

Cluster of Cell Bodies •Nuclei •Ganglia

Axon Bundles •Tracts •Nerves

Neuron Types Interneurons (96% of all neurons)•Integrate information from Afferent neurons & transmit to efferent neurons

Afferent Neurons Cell bodies in PNS (ganglia)•Transmit signals to CNS

Efferent (motor) Neurons Cell bodies in CNS•Transmit signals to Effectors (muscles, glands, etc)

Glial Types •Oligodendria, Astroglia, microglia, ependymal cells

•Schwaan, Satellite cells

Glial Cells

Neurons are the VIP’s of the nervous systems! They need other people to help do their laundry, cook food, act as bodyguards, etc etc so they can focus on their jobs

Neurons

PNS Glial Cells

Schwann Cells form myelin sheath which acts as electrical insulator. Only wrap around 1 cell

• Structure has many layers of cell membrane with gap junctions connecting layers

Neuron

-Gap Junctions

PNS Glial Cells

• Satellite Cells non-myelinating, support nerve cells

CNS Glial Cells-4 Types

• Oligodendrite Myelinating Cell (like Schwaan) but can wrap around more than one neuron

• Astroglia Make contact with blood vessels and neurons; transfer nutrients, maintain microenvironment; Star Shaped.

CNS Glial Cells

• Microglia Small, specialized immune cells -maintain microenvironment like astroglia-remove dead cells & foreign invaders, protect neurons

• Ependymal Cells Epithelial cells, create semi-permeable barriers between brain compartments-produce cerebrospinal fluid

Electrical Properties of Neurons

• Difference between electrical charge on the inside of the cell and the outside environment creates an electrical gradient across the membrane

• There is also an osmotic gradient due to the differences in concentrations of solutes between the inside & outside of cell

Electrical Properties of Neurons

• Cell membranes are semi-permeable- Allow free diffusion of small, hydrophobic (non-

polar) molecules• Membranes a impermeable to most

molecules, Especially charged ions. • Specific protein transporters move these

molecules across the membrane

Resting Membrane Potential

• Resting Membrane Potential for a neuron is around -70 mV to -90 mV Negative charge compared to environment; mostly due to phosphate (HPO4

2- ,H2PO4

-), and negatively charged proteins & DNA

-70 mV- --

---

--

- -+ ++ +

+ ++

+ +

+

Resting Membrane Potential

• Know the relative ion concentrations for the neuron at rest:

• Na+, Cl-, and Ca2+ have concentrations higher in the extracellular fluid (outside cell)

• K+ has a higher concentration inside the cell

-70 mV

K+

Na+

Ca2+Cl-

Na+/K+ ATPase

• Active transport of 3 Na+ out of the cell and 2 K+ into the cell powered by ATP

• Pumps ions against gradient (by consuming energy) to maintain cellular concentrations of K+ and Na+

• Compensates for ions leaking into/out of cell along their concentration gradient

Nernst Equation

• Equilibrium Potential (Eion) is the electrical potential of the Cell needed to generate an equilibrium state for a KNOWN concentration gradient The electrical gradient needed to balance the concentration gradient

• Compare this to known cell potential to predict where ions are likely to flow

Nernst Equation• Know that K+ is found at higher concentrations inside

of the cell Concentration gradient dictates K+ would flow out of the cell

• Calculated Equilibrium Potential for Potassium is -90 mV.

-90 mV

K+

---

-Neuron with membrane potential of -90 mV

No NET K+ movementNegative charges attract Positive K+ to balance concentration gradient

-70 mV

K+

--Neuron with membrane potential of -70 mV

K+ will flow (leak) out of cellNegative charges not enough to attract Positive K+ to remain in the cell

Nernst Equation• Know that Na+ is found at higher concentrations outside of

the cell Concentration gradient dictates Na+ would flow into the cell

• Calculated Equilibrium Potential for Na+ is +60 mV.

+60 mV Na+

Neuron with membrane potential of +60 mV

No NET Na+ movementPositive charges repel Positive Na+ to balance concentration gradient

-70 mV+

--Neuron with membrane potential of -70 mV

Na+ will leak into the cellNegative charges not enough to repel Positive Na+ to prevent movement into cell

Na+

++ + +

Resting Membrane Potential & Ion Permeability

• The relative permeability of these ions dictate how important its contribution to the resting membrane potential is

• Ions that can move more easily through the membrane contribute greater to the RMP

• RMP can be calculated using the Goldman Equation which takes into account the relative permeability of ions

• Permeability can be increased by:1)opening gated protein channels for transport2) increasing the # of transport proteins

Gated ChannelsStretch

Channel Open

Channel Closed

Mechanically Gated- Respond to physical forces- Found in Sensory neurons

Chemically Gated- Respond to ligand binding (neurotransmitters, neuromodulators)- “most important” for neurons (located in synapses)

Voltage Gated- Respond to membrane potential changes- Involved in initiation and conduction of electrical signals

++

+ +Channel Open

Channel Closed

Channel Open

Channel Closed

Changes in Membrane PotentialDepolarization Hyperpolarization

Effect on cell charge Cell becomes less negative (more positive)

Cell becomes more negative

Effect on potential difference

Decreases membrane potential difference

Increases membrane potential difference

Occurs when Lose: Cl- K+, Na+, Ca2+

Occurs when Gain: K+, Na+, Ca2+ Cl-

Occurs (in general): Loss of negative (-)ions, or gain of positive (+) ions

Loss of positive (+) ions, or gain of negative (-) ions

Repolarization is any change in membrane potential which returns it to the Resting Membrane Potential

Graded & Action PotentialsGraded Action

Distance: Short Long

Polarization: Hyperpolization or Depolarization Wave of depolarization followed by repolarization & hyperpolarization

Initiated by: Ion channels opening; usually from neurotransmitters, or mechanically gated channels in sensory neurons

Threshold potential (minimum depolarization) reached at axon hillock (triggering zone) the sum of excitatory and inhibitory graded potentials-Usually Threshold is -55 mV

Strength of signal: Dependant # of ions that enter cell (proportional to strength of trigger); diminishes with distance; can be summed temporally or spatially

Identical strength for all action potentials fired; does not diminish along length of neuron

Location in neuron: Dendrites, cell body

Action Potential

-55 mV

-70 mV

01

2

3

4

5 6

Action Potential-Voltage Gates

++ +

Sodium (Na+) Channel with Activation Gate (opens at -55 mV), and Inactivation Gate (voltage activated but time delayed)

Inactivation Gate

Activation Gate

Na+

Action Potential-Voltage Gates

++

Potassium (K+) Channel with Voltage Gate which opens later than Na+ channels (fully open at +30 mV)

K+

Action Potential

+ +0

MP = Less than -55 mV

+ +1

MP = -55 mV

Action Potential

++

2MP = Between -55 mV and +30 mV

3 &4

MP = +30 mV to -70 mV

Na+

+

K+

+

Action Potential

+5

MP = Less than -70 mV

5.5+

K+

+

K+

+ MP = Less than -70 mV

ABSOLUTE REFRACTORY

RELATIVE REFRACTORY

Refractory Periods

• Set directionality of Signal cannot activate membrane regions which have recently fired

++

Na+

Na+

Na+Na+

+

Action PotentialPhase Membrane

potentialNa+ Channel K+ Channel Ion

MovementActivation Gate Inactivation

Gate

Na+ K+

0 Sub-threshold Stimuli

Less than -55 mV

Closed Open Closed

1 Depolarizing Stimulus

~ -55mV Begin to open

Open Closed In

2 Rapid Depolarization

Between -55 mV and +30 mV

Open Open Slowly begin to open

In

3 Peak ~ +30 mV Open Closed Closed Out

Action PotentialPhase Membran

e potential

Na+ Channel K+ Channel Ion Movement

Activation Gate

Inactivation Gate

Na+ K+

4 Repolarization Less than + 30 mV

Open Closed Open Out

5 Hyperpolarization Less than -70 mV

Closed Closed (absolute refractory)/Open (relative)

Open Out

6 Resting Membrane Potential

-70 mV Closed Open Closed

Synapses• Electrical Synapses Gap junctions connect 2

cells allowing direct electrical signalling- CNS; between 2 neurons, or neuron and glial cell- Nervous system development and transmission in adult brain

Action Potential Depolarization wave Action Potential

Depolarization wave

Chemical Synapse

Synaptic Cleft

Presynaptic cell Postsynaptic cell

Ca2+

Action Potential Depolarization wave

Ions

AP causes Ca+2 entry vesicles release neurotransmitter

Neurotransmitter Receptors can either open ion channel directly, or cause another (long lasting) signal cascade coupled to G proteins etc

Types of NeurotransmittersNeurotransmitter DescriptionAcetylcholine Synthesized from acetyl CoA by Choline Acetyl Transferase (CAT) at axon

terminal.Degraded for deactivation and then recycling by Acetylcholinesterase-Used by cholinergic receptors: a) Muscarinic Slow, G protein coupled b) Nicotinic Fast, ACh binds directly to ion channel

Biogenic Amines Contain amine group (NH2) derived from amino acids, synthesized at axon terminal

Amino Acids Very abundant in CNSExcitatory Glutamate, aspartateInhibitory Glycine, gamma-aminobutyric acid (GABA)

Neuropeptides Synthesized the same as regular proteins, in rough ER, packaged by Golgi apparatus

Types of NeurotransmittersNeurotransmitter DescriptionPurines Nucleotides nucleotides bind purinergic receptors in CNS

e.g. Adenosine, AMP, ATP

Gases Nitric Oxide (NO) synthesized from oxygen and arginine by Nitric Oxide Synthase-Synthesized and then immediately used (not stored)-Unstable and degrades quickly

Peripheral Nervous SystemAutonomic Division Somatic division

Structure of Relay 2 neuron chain Single neuron

Controls Smooth and cardiac muscle, glands, smooth muscle, and adipose tissue

Skeletal Muscle Can only cause muscle excitation, not inhibition

Neurotransmitters -Acetylcholine & Norepinephrine -Acetylcholine (Ach) in vesicles

Muscle Cell

CNS

ACh Nicotinic ACh receptors

Somatic neuron Always excitatory

Target CellTarget Cell

CNS

Ganglion

Sympathetic 2 Neuron Chain

Parasympathetic 2 Neuron chain

LegendAcetylcholine

Norepinephrine

Nicotinic ACh Receptors

Muscarinic ACh Receptors

Adrenergic Receptors

Swollen Terminals Varicosity; stores a lot of neurotransmitter

Adrenergic ReceptorsType of Adrenergic Receptor

Associated Tissues/ Neurons

Neuro-transmitter Secreted by:

Respond to: Pathway of Response

α Many tissues; post-ganglionic symp. Neurons

Norepinephrine better than Epinephrine

G protein Ca2+ channels increase in cellular [Ca2+]

β1 Heart, muscle, kidney;

post-ganglionic symp. Neurons

Norepinephrine and epinephrine equally

G protein cAMP production

β2 Blood vessels, smooth muscle;

post-ganglionic symp. neurons

Epinephrine better than Norepinephrine

G protein cAMP production

Cholinergic ReceptorsType of Cholinergic Receptor

Receptor located on:

Respond to: Pathway of Response

Nicotinic Muscles (somatic system), post ganglionic nerves of autonomic system

ACh, nicotine (agonist)

ACh binds Na+ channels intracellular [Na+] increases depolarization-Excitatory

Muscarinic Tissues of parasympathetic system

ACh, muscarine (agonist)

G proteins close/open ion channels-Inhibitory or excitatory

Muscles• Tissues specialized to convert biochemical

reactions into mechanical work• Generate force, motion, & heat1) Skeletal attached to skeleton, responsible for

movement; has striations2) Smooth internal organs; influences movement

of materials through body no striations3) Cardiac Heart muscles; pumps blood; has

striations

Skeletal Muscles

• Attach to bones via tendons at 2 points;- Origin at “least” moveable part of body-Insertion at “most” moveable part of body

• Flexor Muscles contraction brings bones closer together

• Extensor Muscles contractions moves bones away from another

• Flexor & Extensor are antagonistic pairs

Muscle StructureEpimysium- outer connective tissue

Fascicles- Bundles of individual Muscle Fibers each wrapped in a connective tissue sheath (Endomysium)

Perimysium- contains Nerves & blood vessels surround fascicles

Muscle Fibres

• Muscle Fibres = Muscle Cells• Contain mostly Myofibrils Functional unit of muscle• Energy from mitochondria (oxidative phosphorylation ATP synthesis) and glycogen granules (glucose storage)

• Cell membrane SarcolemmaCytoplasm SarcoplasmModified Endoplasmic Reticulum Sarcoplasmic Reticulum Sequester Ca2+ for rapid release into cell

Muscle Fibres- ProteinsProtein Class DescriptionActin Contractile Individual subunits (Globular G-actin) form filamentous, F-Actin

2 F-Actin chains twist together to form “thin filament” with troponin and tropomyosin

Myosin Contractile 2 rigid regions (head and tail) connected by flexible “hinge”250 molecules join to form “thick filament”Myosin Heads bind onto F-Actin (form cross-bridges)Motor protein- Powered by ATP

Tropomyosin Regulatory Can either block (“off”) or allow (“on”)binding of myosin head on F-Actin

Troponin Regulatory -Made of 3 subunits, most important for regulation it troponin C-Can change position of tropomyosin to either “on”/”off”

Tintin, Nebulin, alpha actinin, etc

Accessory Tintin- Largest known protein, elastic, returns muscles to resting lengthNebulin- Helps align actin filaments, organizational role (?)

Practice Questions

Practice Questions

• The teleological approach to physiology:a) Explains “how” a process occursb) Examines how an organism maintains a stable

internal environmentc) Describes the “Function” of a systemd) Describes the “Process” of a system

Practice Questions

• Which of the following is NOT an example of homeostatis?

a) Maintaining a blood pH level of ~7b) Keeping blood [Na+] within a normal rangec) A snakes body temperature matching that of

its environmentd) Negative feedback controlling blood pressuree) All of the above are homeostatic

Practice Questions

• Which of the following are types of connective tissue?

a) Adiposeb) Bonec) Bloodd) Skeletal musclee) Loose, elastic

Practice Questions

• _______, and ______ are associated with local communication, while ______ are a component of long distance communication

a) Paracrines, Autocrines, Acetylcholineb) Paracrines, Autocrines, Endocrines c) Neurotransmitters, Connexons, Endocrinesd) Endocrines, Paracrines, Autocrinese) None of the Above

Practice Questions

• The type of signalling molecule determines the response that occurs in the cell

a) Trueb) False

Practice Questions

• Which of the following pairs are analogous in the CNS and PNS

a)Nuclei; Gangliab) Tracts; Nervesc) Oligodendria; Schwann cellsd) All of the Abovee) None of the Above

Practice Questions

• Efferent Neuronsa) Are a part of the sympathetic nervous systemb) Are the main component of the CNSc) Carry information to the CNSd) Have cell bodies within the CNSe) Include auditory nerve cells which sense

sound

Practice Questions

• Which is NOT true of Glial Cellsa) They outnumber neuronsb) They do not carry electrical signalsc) They Insulate neurons for better signal

conductiond) They can remove dead/foreign cellse) All of the above are true

Practice Questions• A new element is discovered at high concentrations in the

extracellular fluid of neural tissue in an ionic form. The ion, J-2 has a negative charge and the cell membrane is completely impermeable to this ion. Which of the following are true statements:

a) The ion has a significant impact on the resting membrane potential of neurons

b) If J-2 were allowed to enter the cell it would be hyperpolarizingc) If J-2 were allowed to enter the cell as part of a graded potential,

it would help trigger an Action Potentiald) Osmotically speaking, the concentration gradient forces the ion

out of the neuron.e) None of the above

Practice Questions

• Which of the following is found at relatively low concentrations in the resting neural cell

a) K+

b) Phosphatec) Ca2+

d)Na+

e) B, C, Df) C, D

Practice Questions

• A Positive ion is calculated to have an equilibrium potential of -20 mV. The ion will have a tendency to leak out of the cell:

a) At resting membrane potentialb) At the peak of an action potentialc) During the refractory periodd) None of the above

Practice Questions

• Graded Potentialsa) Always cause depolarizationb) Can be summer temporally and spatiallyc) Can travel long distancesd) Can only be caused by Na+ transporte) None of the above

Practice Questions

• During the rising (depolarization) phase of an action potential

a) The sodium channel is openb) The Na+/K+ ATPase is inactivec) The cell is undergoing a positive feedback loopd) The Potassium channel is pumping K+ into the

celle) A and C

Practice Questions

• What determines the threshold potential of a neuron?

a) The properties of the voltage gated potassium channel

b) The resting membrane potentialc) The properties of the voltage gated sodium

channeld) Excitatory Post Synaptic Potentialse) None of the above

Practice Questions

• The absolute refractory period:a) Last ~ 1 msecb) Prevents an action potential from occurring

unless a suprathreshold stimulus is appliedc) Occurs because the potassium channel is closedd) Ensures action potentials move in one directione) A and D

Practice Questions

• Which of the following is NOT a method to reduce resistance in nerves?

a) Lowering the surface area: volume ratio of a nerve

b) Having giant axonsc) Wrap cells in myelin sheathd) Increasing ionic leaking through the cell

membrane

Practice Questions

• When Ca2+ channels in the axon terminal opena) The axon terminal was recently depolarized

by an action potentialb) Neurotransmitter will be releasedc) Calcium flows out of the cell into the synaptic

cleftd) A and Be) All of the above

Practice Questions

• Nitric Oxidea) Is a stable gasb) Is synthesized by Nitric Oxide Synthasec) Is stored in neurotransmitter vesiclesd) Is a biogenic amine type neurotransmittere) All of the above

Practice Questions

• Acetlycholinea) Is synthesized from acetate and cholineb) Is degraded in the synapse by

acetylcholinesterasec) Is released by neurons of the parasympathetic

pathway, but not the sympatheticd) Will not bind to muscarinic receptorse) None of the above

Practice Questions

• Which of the following is true with regards to nicotinic receptors?

a) They bind nicotine as an antagonistb) They act via ion channelsc) They are a slow synaptic potential using G proteinsd) They are found on tissues of the parasympathetic

pathwaye) None of the Above

Practice Questions

• Somatic neurons:a) Have a single neuron between the CNS and

muscle fibreb) Each control a distinct motor unitc) Release ACh which binds adrenergic receptorsd) Are afferent neuronse)A and B

Practice Questions

• Which is true of skeletal muscles?a) They can only contractb) They generate both motion and forcec) They do not control the contractions of the

heartd) They appear striated under a microscopee) All of the above

Practice Questions

• The role of Troponina) Involves the binding of calcium ionsb) Involves the interaction with nebulinc) Activates contraction in the absence of Ca+2

d) Involves a direct interaction with ryanodine receptors

e) None of the above

Practice Questions

• The Thin Filament is:a) Composed of G Actinb) Composed of F Actinc) Composed of Myosind) Makes up the M Linee) Is the only component of the H zone

Practice Questions

• The “Power Stroke” of a myosin molecule:a) Involves the release of ADPb) Requires Ca2+ to be bound to tropomyosinc) Moves consecutive Z discs further apartd) Requires the release of inorganic phosphate

Practice Questions

• At the motor end plate:a) ACh is bound nicotinic andrenergic receptorsb) K+ efflux exceeds Na+ influx when Na+/K+

channels are openc) Curare can block receptorsd) DHP receptors bind ACh

Practice Questions

• Muscles can use energy from:a) Oxidative phosphorylationb) ATPc) Glycolysisd) Creatine-Phosphatee) All of the above

Practice Questions

• Which is true of Slow-twitch oxidative muscle fibres?

a) They have a lower threshold for recruitment then fast-twitch glycolytic

b) They are easily fatiguedc) They are Red in colourd) The have a fast myosin ATPasee) A and Cf)B and D

Practice Questions

• Isometric muscle contraction:a) Moves the bodyb) Does not create forcec) Has muscle length changed) Has sarcomeres shortene) None of the above

Practice Questions

• β1 type receptors are:a) Cholinergic receptorsb) Are responsive more to norepinephrine than

epinephrine c) Increase cAMP production when actived) Increase cytosolic Ca+2 levels

Practice Answers

Practice Questions

• The teleological approach to physiology:a) Explains “how” a process occursb) Examines how an organism maintains a stable

internal environmentc) Describes the “Function” of a systemd) Describes the “Process” of a system

Practice Questions

• Which of the following is NOT an example of homeostatis?

a) Maintaining a blood pH level of ~7b) Keeping blood [Na+] within a normal rangec) A snakes body temperature matching that of

its environmentd) Negative feedback controlling blood pressuree) All of the above are homeostatic

Practice Questions

• Which of the following are types of connective tissue?

a) Adiposeb) Bonec) Bloodd) Skeletal musclee) Loose, elastic

Practice Questions

• _______, and ______ are associated with local communication, while ______ are a component of long distance communication

a) Paracrines, Autocrines, Acetylcholineb) Paracrines, Autocrines, Endocrines c) Neurotransmitters, Connexons, Endocrinesd) Endocrines, Paracrines, Autocrinese) None of the Above

Practice Questions

• The type of signalling molecule determines the response that occurs in the cell

a) Trueb) False

Practice Questions

• Which of the following pairs are analogous in the CNS and PNS

a)Nuclei; Gangliab) Tracts; Nervesc) Oligodendria; Schwann cellsd) All of the Abovee) None of the Above

Practice Questions

• Efferent Neuronsa) Are a part of the sympathetic nervous systemb) Are the main component of the CNSc) Carry information to the CNSd) Have cell bodies within the CNSe) Include auditory nerve cells which sense

sound

Practice Questions

• Which is NOT true of Glial Cellsa) They outnumber neuronsb) They do not carry electrical signals (they do

over short distances)c) They Insulate neurons for better signal

conductiond) They can remove dead/foreign cellse) All of the above are true

Practice Questions• A new element is discovered at high concentrations in the

extracellular fluid of neural tissue in an ionic form. The ion, J-2 has a negative charge and the cell membrane is completely impermeable to this ion. Which of the following are true statements:

a) The ion has a significant impact on the resting membrane potential of neurons

b) If J-2 were allowed to enter the cell it would be hyperpolarizingc) If J-2 were allowed to enter the cell as part of a graded potential,

it would help trigger an Action Potentiald) Osmotically speaking, the concentration gradient forces the ion

out of the neuron.e) None of the above

Practice Questions

• Which of the following is found at relatively low concentrations in the resting neural cell

a) K+

b) Phosphatec) Ca2+

d)Na+

e) B, C, Df) C, D

Practice Questions

• A Positive ion is calculated to have an equilibrium potential of -20 mV. The ion will have a tendency to leak out of the cell:

a) At resting membrane potentialb) At the peak of an action potential (+30 mV is

greater than -20 mV)c) During the refractory periodd) None of the above

Practice Questions

• Graded Potentialsa) Always cause depolarizationb) Can be summer temporally and spatiallyc) Can travel long distancesd) Can only be caused by Na+ transporte) None of the above

Practice Questions

• During the rising (depolarization) phase of an action potential

a) The sodium channel is openb) The Na+/K+ ATPase is inactivec) The cell is undergoing a postive feedback loopd) The Potassium channel is pumping K+ into the

celle) A and C

Practice Questions

• What determines the threshold potential of a neuron?

a) The properties of the voltage gated potassium channel

b) The resting membrane potentialc) The properties of the voltage gated sodium

channeld) Excitatory Post Synaptic Potentialse) None of the above

Practice Questions

• The absolute refractory period:a) Last ~ 1 msecb) Prevents an action potential from occurring

unless a suprathreshold stimulus is appliedc) Occurs because the potassium channel is closedd) Ensures action potentials move in one directione) A and D

Practice Questions

• Which of the following is NOT a method to reduce resistance in nerves?

a) Lowering the surface area: volume ratio of a nerve

b) Having giant axonsc) Wrap cells in myelin sheathd) Increasing ionic leaking through the cell

membrane

Practice Questions

• When Ca2+ channels in the axon terminal opena) The axon terminal was recently depolarized

by an action potentialb) Neurotransmitter will be releasedc) Calcium flows out of the cell into the synaptic

cleftd) A and Be) All of the above

Practice Questions

• Nitric Oxidea) Is a stable gasb) Is synthesized by Nitric Oxide Synthasec) Is stored in neurotransmitter vesiclesd) Is a biogenic amine type neurotransmittere) All of the above

Practice Questions

• Acetlycholinea) Is synthesized from acetate and cholineb) Is degraded in the synapse by

acetylcholinesterasec) Is released by neurons of the parasympathetic

pathway, but not the sympatheticd) Will not bind to muscarinic receptorse) None of the above

Practice Questions

• Which of the following is true with regards to nicotinic receptors?

a) They bind nicotine as an antagonistb) They act via ion channelsc) They are a slow synaptic potential using G proteinsd) They are found on tissues of the parasympathetic

pathwaye) None of the Above

Practice Questions

• Somatic neurons:a) Have a single neuron between the CNS and

muscle fibreb) Each control a distinct motor unitc) Release ACh which binds adrenergic receptorsd) Are afferent neuronse)A and B

Practice Questions

• Which is true of skeletal muscles?a) They can only contractb) They generate both motion and forcec) They do not control the contractions of the

heartd) They appear striated under a microscopee) All of the above

Practice Questions

• The role of Troponina) Involves the binding of calcium ionsb) Involves the interaction with nebulinc) Activates contraction in the absence of Ca+2

d) Involves a direct interaction with ryanodine receptors

e) None of the above

Practice Questions

• The Thin Filament is:a) Composed of G Actinb) Composed of F Actinc) Composed of Myosind) Makes up the M Linee)Makes up the I Bandf)B and E

Practice Questions

• The “Power Stroke” of a myosin molecule:a) Involves the release of ADPb) Requires Ca2+ to be bound to tropomyosinc) Moves consecutive Z discs further apartd) Requires the release of inorganic phosphate

Practice Questions

• At the motor end plate:a) ACh is bound nicotinic andrenergic receptorsb) K+ efflux exceeds Na+ influx when Na+/K+

channels are openc) Curare can block receptorsd) DHP receptors bind ACh

Practice Questions

• Muscles can use energy from:a) Oxidative phosphorylationb) ATPc) Glycolysisd) Creatine-Phosphatee) All of the above

Practice Questions

• Which is true of Slow-twitch oxidative muscle fibres?

a) They have a lower threshold for recruitment then fast-twitch glycolytic

b) They are easily fatiguedc) They are Red in colourd) The have a fast myosin ATPasee) A and Cf)B and D