Communication

Question 1

Peripheral Nervous System

Answer 1

Many cells and neurons within a nerve

Nerves and ganglia

Two dimensional flow

Communication link between CNS and rest of body

PNS—nerves to face, nerves to lower limb

Question 2

Central nervous system

Answer 2

CNS— brain, spinal cord

Question 3

Motor division of the PNS

Answer 3

Efferent (away)

AP from CNS to effector organs (ie/ muscles and glands)

Question 4

Somatic nervous system

Answer 4

Voluntary

AP from CNS — skeletal muscles

Somatic nervous system—Effectors: skeletal muscle=movement

Modification of movement
Motor output: movement changes in metabolism, heart rate, breathing rate,etc.

Question 5

Autonomic nervous system

Answer 5

Involuntary

Autonomic nervous system—(sympathetic division, parasympathetic division)—- effectors

Sympathetic—antagonist, stress, increased heart rate

Parasympathetic—antagonist, rest, decreased heart rate

AP from CNS—effectors—effectors:cardiac and smooth muscle glands

Modification of movement
Motor output: movement changes in metabolism, heart rate, breathing rate,etc.

Question 6

Enteric division

Answer 6

Part of PNS

has both sensory and motor neurons contain within digestive tract

Can function without input from CNS or other parts of PNS

Normally integrated with CNS by sensory neurons and ANS motor neurons

Question 7

Nervous system

Answer 7

The Nervous System is a communication system that is involved in the coordination of
almost all body functions— coordinates body to maintain homeostasis

It is designed to receive signals from the internal and external environment

The signals are then interpreted to determine whether to stimulate or inhibit the activity of organs, tissues and cells throughout the body

One of the main objectives is the maintenance of homeostasis, or a relatively stable internal environment

Question 8

Input(sensory input)

Answer 8

special senses - vision, hearing, taste, pain, body position

homeostasis - blood pressure and carbon dioxide levels, ion levels (pH (H+))—processes subconsciously

Sensory receptors monitor numerous external and internal stimuli

Question 9

Integration

Answer 9

Brain and spinal cord

a pain stimulus may trigger an immediate reflex, or it may be ignored or stored as a memory

A soccer player processes information about her own body position and speed, as well as that of the ball, her team-mate and opponents in order to produce the muscle contractions needed to send a perfect pass

Question 10

Output

Answer 10

Control of muscle contraction and glandular secretion of hormones—contract only when stimulated by nervous system—controls major movement of body, also controls cardiac and smooth muscles and many glands

Maintenance of Homeostasis - increased carbon dioxide in the blood stimulates breathing rate

Depends on nervous systems ability to detect, interpret and respond to changes in internal and external conditions

Can stimulate or inhibit other system to help maintain a constant internal environment

Maintaining Mental Activity—consciousness, memory and thinking

Question 11

Neurons

Answer 11

Neurons are one of the main cell type within the Nervous system

Receive stimuli, conduct APs and transmit signals to other neurons or affector organs

Neurons have three structures facilitating the separate functions

have dendrites, cell body and axons

The different types of neurons illustrated in Figure 8.4 have different structures, which
provides with a good indication of their main functional roles

Question 12

dendrites

Answer 12

input (dendrites)—short, highly branched, receive info, transmit info toward cell body

Question 13

cell body

Answer 13

processing (cell body)—contains single nucleus(source of info for gene expression)

Question 14

axon

Answer 14

output (axons)—single long cell process, axon hillock(area where axon leaves neurons cell body

Question 15

Multipolar neuron

Answer 15

Many dendrites

Large cell body

Lots of inputs require lots of processing

Most of the neurons within the CNS

Most neurons. Ie/motor

has many dendrites and an axon

Question 16

Bipolar neuron

Answer 16

Few dendrite

Small cell body

Axon-have two processes

More conduction, not as much

Sending directly to nervous system

Ie/sight and smell

has a dendrite and an axon

Question 17

Pseudo-unipolar neuron

Answer 17

Limited processing

Simple relay of signal with little processing

Axon branches function as a single axon

One process extends to periphery and other to CNS

Ie/most sensory neurons

appears to have an axon and no dendrites

Question 18

Gilal cells

Answer 18

These cells do not conduct AP’s

Glial Cells are the other main cell type in the Nervous system. They perform structural support and protective roles by contributing to the blood-brain barrier (prevents movement of some molecules”that are dangerous to brain” and compounds into the brain), as well as immune and nutrient

Provision functions: enhance neuron function and maintain normal conditions within nervous tissue

most retain ability to divide

More than neurons

Question 19

glial cells of the CNS

Answer 19

astrocytes
ependymal cells
microglia
oligodendrocytes

Question 20

glial cells of the PNS

Answer 20

Schwann cells
satellite cells

Question 21

astrocytes

Answer 21

Highly branched

Stimulate or inhibit the signaling activity, help limit damage to neural tissue—prevent harmful molecules from getting to brain

Provide structural support; regulate neuronal signaling; contribute to blood-brain”blood and CNS” barrier;help with neural tissue repair

Question 22

Ependymal cells

Answer 22

Epithelial-like

Line ventricles of brain and central canal of the spinal cord, circulate cerebrospinal fluid(CSF)”line fluid filled cavaties,some help move CSF”; some form of choroid plexuses, which produce CSF

Question 23

Microglia

Answer 23

Small, mobile cells

Protect CNS from infection;become phagocytic in response to inflammation

Immune cells, remove bacteria and cell debris

Engulf and break down other cells(response to inflammation)

Question 24

Oligodendrocytes

Answer 24

Cells with processes that can surround several axons

Cell processes from myelin sheaths around axons or enclose unmyelinated axons in the CNS

Facilitate speed. Myelin=speed

Question 25

Schwann cells

Answer 25

Single cells surrounding axons Form myelin sheaths around axons and enclose unmyelinated axons in the PNS

Question 26

Statelite cells

Answer 26

Single cells surrounding cell bodies Support neurons, providing nutrients; project neurons from heavy-metal poisons

Question 27

Myelin

Answer 27

Specialized glial cells form coatings (myelin sheaths) around axons greatly increasing the velocity at which they can conduct action potentials (electrical signals) Increased speed and efficiency of AP’s

Question 28

specialized glial cells that form myelin

Answer 28

Specialized glial cells form coatings (myelin sheaths) around axons greatly increasing the velocity at which they can conduct action potentials (electrical signals) Within the Central Nervous System these cells are called Oligodendrocytes Within the Peripheral Nervous System these cells are called Schwann cells Repeatedly wraps around a segment of an axon to form a series tightly wrapped cell membranes

Question 29

Nodes of Ranvier

Answer 29

gaps between myelin sheaths, about every millimeter along axon (a) allows for ion movement and faster conduction compared to unmyelinated axons (b) Depolarization, electrical sheath jumps

Question 30

Electrical Communication

Answer 30

Cell membrane creates a semi permeable barrier, selectively allowing the movement of ions In cells that have electrical properties (e.g. nerve, muscle) there are different environments inside and outside the cell, with an uneven distribution of types of ions. The membrane becomes polarized, with the inside being more negatively charged than the outside. This creates an electrical potential across the cell membrane Polarity is a stored gradient that when opened will result in movement based on the chemical ([ ] gradient) and electrical potential (electrical gradient) Potential energy used in secondary active transport of glucose—stored NRG Sodium down both -Chemical gradient -Electrical gradient

Question 31

Resting Membrane Potential

Answer 31

Potential we see when we are able to form an AP There are ion channels that are always open (leak ion channels) and ion channels that open when specific signals are present (gated ion channels) Leak ion channels—more K+ ones than sodium, resting membrane has greater K+ permeability than Na+—K+ has greater influence on RMP Gated ion channels can be signaled to open by chemicals (chemically gated) or electrical changes (voltage gated) Cl- movement is limited Results from the differences in the CJ’s of ions across the membrane and its permeability characteristics Sodium (Na+) concentration gradient into cell — higher CJ outside Potassium (K+) concentration gradiant out of cell—50-100X more than Na+.—higher CJ inside Leak channels allow some ion movement—down [ ] gradiant.—always open Sodium – Potassium pump – active transport of Na+ out and K+ in maintains resting membrane potential— to compensate for constant leakage of ions across the membrane maintains greater [ ] of Na+ outside cell, and let inside Negative inside cell } electrical Positive outside cell} potential Uneven distribution means membrane is polarized established by leak channels and sodium potassium pump (maintain the negative inside the cell)

Question 32

Action Potential

Answer 32

electrical signals conducted along a cell membrane (neuron, muscle cell) Occurs either via continuous conduction—unmylinated, Or saltatory conduction—mylinated AP conducts across RMP changes in response to stimuli at rest voltage gated channels are closed Following NT activation Membrane potential depolarizes during an Action Potential Action Potentials are all or none – always the same magnitude one initiated— either going or not AP Initiated by local threshold potential being reached Resting Membrane potential – 70mV Action Potential Membrane Potential Depolarizes to +20 mV Repolarizes to -70 mV Resting membrane potential in recovery established by leak channels and Na+/K+ pump—maintain (-) inside cell

Question 33

3 stages of neuronal communication

Answer 33

1. Generation of Action Potential in cell body 2. Action potential propagation along axon Communication with target cell at 3. synapse conversion to Chemical communication

Question 34

Hyperpolarization

Answer 34

More negative than RMP, elevated permeability to K+ last a very short time

Question 35

Depolarization

Answer 35

Rising phase open voltage gated Na+ channels—increased membrane brief reversal of charge where inside is more positive permeability to Na+ Open when local membrane potential reaches threshold (reached after At axon hillock) Positive sodium ions move in —cause local current, inside of membrane to become positive.—results in local potential (if strong enough will become AP)

Question 36

Repolarization

Answer 36

Na+ channels close, voltage gated K+ channels open Positive potassium ions move out Na+/K+ pump works to re-establish resting membrane potential

Question 37

Tetrodotoxin

Answer 37

Pufferfish Prevents AP in nerve cells Blocks sodium channels Prevents action potential in nerve cells Acts on Central and Peripheral NS If u eat it—Paresthesia (tingling) in mouth, then extremities Weakness, lack of coordination, paralysis, cyanosis (blue skin – due to compromised breathing) Death often within 4-6 hours

Question 38

Synapse

Answer 38

junction where the neuron interacts with another neuron or cell conversion of electrical message in axon into chemical message sent to next cell Close enclosed space

Question 39

Presynaptic terminal

Answer 39

terminal (before synapse) End of axon forms Action Potential trigger voltage gated Calcium Channels Calcium moves in and stimulates vesicles to—stimulates vesicles to send message contents release neurotransmitter into synaptic cleft (space between cells)

Question 40

Postsynaptic membrane

Answer 40

membrane (after synapse) Neurotransmitter binds receptors on post synaptic membrane Opening or closing chemically gated channels for Sodium(Na+), Potassium (k+), Chloride(Cl-)negative effect.—(chemical signal)—stored in synaptic vesicles in presynaptic terminal

Question 41

Synaptic Cleft

Answer 41

Space separating the presynaptic and postsynaptic membrane

Question 42

Acetylcholine (ACh)—(excitatory or inhibitory effect)

Answer 42

Decrease in Alzheimer’s patients Site of release:CNS synapses, ANS synapses, and neuromuscular junctions Effect:excitatory or inhibitory Clinical examples: Alzheimer disease (a type of senile dementia) is associated with a decrease in acetylcholine-secreting neurons. Myasthenia gravis (weakness of skeletal muscles) results from reduction in acetylcholine receptors

Question 43

Norepinephrine (NE)—(excitatory or inhibitory effect)

Answer 43

Site of release:Selected CNS synapses and some ANS synapses Effect:excitatory Clinical examples:Cocaine and amphetamines increase the release and block the reuptake of norepinephrine, resulting in overstimulation of postsynaptic neurons

Question 44

Neurotoxin—(cobra venom)

Answer 44

Venom blocks receptors for the neurotransmitter Acetylcholine (Ach) on the post synaptic membrane— gets in there, but you can’t stimulate venom is similar in structure to Ach unable to stimulate muscle contraction numbness and paralysis breathing impacted as respiratory muscles paralyze

Question 45

Surviving a snakebit

Answer 45

Call for emergency help immediately and note time of bite(so we know progression) While waiting— Wash bite with soap and water, Keep bitten area lower than heart, Monitor heart rate and breathing Remember what the snake looked like know the types of snakes in your area - identification of the snake is important as different types of venom can cause nervous system disfunction, impact blood clotting, cause local or widespread cell death Doctor may do blood analysis to determine the type of venom Antivenin specific to the type of snake may be used if appropriate and available

Question 46

Spinal cord

Answer 46

collection of tracts leading to (ascending)-“sensory” and from (descending) the brain Extends from foramen magnum to base of skull—second lumber vertebrae

Question 47

Gray matter

Answer 47

Gray matter – groups of neuron cell bodies and dendrites – forms cortex or nuclei (CNS), ganglion (PNS) When very little myelin gray matter on surface of brain is called the cortex Clusters of gray matter deeper within brain called nuclei

Question 48

White matter

Answer 48

bundles of parallel axons and their myelin sheaths – formal propagate APs, nerve tracts (CNS), nerves (PNS) More info passing In PNS, cluster of neuron cell bodies is called a ganglion

Question 49

Spinal cord injury

Answer 49

transection (complete cut) of the spinal cord results in loss of all sensation and voluntary movement inferior (below) to the point of damage

Question 50

The patient is paraplegic

Answer 50

paralysis of both lower limbs - if the transection occurs below the cervical segment of the spinal cord

Question 51

respiratory failure

Answer 51

If the transection is above C4, the patient may die of respiratory failure

Question 52

Reflex arc

Answer 52

1. sensory receptor - get stretch, stretch receptor is activatied 2. sensory neuron to spinal cord stimulates motor neuron to send signal to brasin - conducts AP to spinal sord 3. descending neuron - synapse with neurons of the stretch reflex 4. motor neuron to muscle - out ventral horn - synapses with sensory neurons in gray matter of spinal cord 5. effector organ (muscle) - simple reflex arcs do not have interneurons - motor neurons from spinal cord extend to same muscle. Stimulating contraction and producing knee jerk response

Question 53

patient is quadriplegic

Answer 53

(no control over limbs) if the cord is transected superior to C5

Question 54

Withdrawal reflex

Answer 54

Withdrawal reflex (removing body from painful stimulus)

Question 55

Converging pathway

Answer 55

Two or more neuron synapse with same postsynaptic neuro Allows information transmitted in more than one pathway to converge into single pathway It takes more than a single AP to have an effect mostly Not usually large enough

Question 56

Diverging pathway

Answer 56

Axon from one neuron divides and synapses with more than one other postsynaptic neuron Allows transmitted information in one neural pathway to diverge into two or more pathways It takes more than a single AP to have an effect mostly Not usually large enough

Question 57

Spatial summation

Answer 57

When local potentials originate from different locations on postsynaptic neuron Can lead to stimulation or inhibition Will determine if integrated potentials will generate AP

Question 58

Temporal summation

Answer 58

When local potentials overlap in time can lead to stimulation or inhibition will determine if integrated potential will generate AP

Question 59

The brainstem

Answer 59

Involved in body functions essential for survival Damage to small areas can cause death Connect spinal cord to rest of brain Regulation of heart rate, breathing, blood pressure— integrated signals from all over body, ie/PH, O2 rates

Question 60

pons

Answer 60

relay info between cerebrum and cerebellum. breathing, swallowing, balance

Question 61

medulla oblongata

Answer 61

important for vital bodily functions

Question 62

Corpus callosum

Answer 62

connects sides of brain

Question 63

Frontal lobe

Answer 63

voluntary motor function, motivation, aggression and mood

Question 64

Parietal Lobe

Answer 64

receiving and perceiving sensory information

Question 65

Occipital Lobe

Answer 65

Visual input

Question 66

Temporal Lobe

Answer 66

Smell, hearing, memory Olfactory smell

Question 67

Insula

Answer 67

Perception of taste

Question 68

Primary sensory areas

Answer 68

Where sensations are perceived

Question 69

Central sulcus

Answer 69

Separates frontal and parietal lobes

Question 70

Voluntary movement

Answer 70

Signal initiated in the Motor Cortex region of brain Descending tracts cross over to opposite side prior to entering spinal cord—going top to bottom Motor neuron leaves spinal cord at ventral root

Question 71

Cerebellum

Answer 71

comparative function – intended movement compared with sensory feedback Modify intended movement Necessary for smooth coordinated movements and learning movements compares feedback from proprioceptive (body position)”where we are in space” neurons in joints and muscles Alcohol inhibits the function of the cerebellum – impairing motor function— more jerky movements

Question 72

Autonomic Nervous System

Answer 72

Unconscious control of smooth muscle, cardiac muscle, organs and glands—(not thinking of them)

Question 73

Sympathetic Division

Answer 73

Activation prepares us for physical activity in response to stressors Fight or flight response Increased heart rate, breathing rate, blood pressure Circulation to muscles Slow digestive functions

Question 74

Parasympathetic Division

Answer 74

Activation prepares body for resting and digestion Decreased heart rate, breathing rate, blood pressure Circulation to stomach and intestines Enhance digestive functions

Question 75

Continuous conduction

Answer 75

non-myelinated axons Slow APs AP in one part of cell membrane stimulates local currents in adjacent membrane AP can occur in one of two ways

Question 76

saltatory conduction

Answer 76

Myelinated axons Increased conduction velocity Don’t need to travel across entire cell membrane AP can occur in one of two ways

Question 77

Sympathetic nerves

Answer 77

Originate from Thoracic (Chest) spine Ganglion close to vertebrae Norepinephrine is Neurotransmitter

Question 78

Para sympathetic nerves

Answer 78

Originate from Cranial nerves (head) and Sacral (tailbone) spine Ganglion close to target Acetylcholine is Neurotransmitter