Human Biology 175 Section 1...

Lecture Notes: Nervous System, of 10

Human Biology 175

Lecture Notes: Nervous System

Section 1 Introduction

A) Master controller and communication system of entire body

1) Thoughts/Emotions/Actions

2) Communication through __________________

B) 3 Overlapping Functions

1) _________________

a) Sensory receptors monitor changes in environmental stimuli

b) Nervous impulses transmit information to brain/spinal cord for processing.

2) _________________

a) Brain/spinal cord neurons

b) process incoming information and determine appropriate response

c) Issue commands as nervous impulses

3) _________________

a) Motor neurons carry commands to effectors

b) Effectors: glands secrete/muscles contract

C) Organization

1) Structural Classification

a) _________________

(1) Brain and spinal cord

(2) Dorsal body cavity

(3) Integration

b) _________________

(1) Cranial and spinal nerves

(2) Outside CNS

(3) Sensory and motor information

2) Functional Classification—only considered with PNS

a) _________________

(1) Conveys continuous sensory information to CNS

(2) _________________________ skin/joints

(3) _________________________ internal organs/structures

b) _________________

(1) MOTOR OUTPUT: Conveys motor information to effectors (muscles/glands)

(2) __________________________ voluntary/conscious control of skeletal muscles

(3) __________________________ Involuntary control over smooth/cardiac muscle and glands

(a) Sympathetic nervous system

(b) Parasympathetic nervous system


Section 2 Nervous Tissue

A) 2 Basic cell types:

1) __________________ generate nervous/electrical impulses

2) __________________ Support cells

B) Neurons

1) General

a) _________________ capable of generating a nervous impulse

b) _________________ (lack centrioles)

c) _________________ processes with a receptive membrane—capable of detecting changes in

stimuli

d) _________________ metabolic center

e) _________________ (single) terminus contains neurotransmitters

f) _________________ gaps between neurons

2) Functional Classification of Neurons

a) _________________

(1) specialized membrane that detects changes in

stimuli and sends the information as an

impulse to the CNS

(2) Special senses

(3) Cutaneous sensory receptors

(4) Proprioceptors (joint/body position)

b) _________________

(1) Located entirely within CNS

(2) Integration/information processing

c) _________________ Relays commands from the

CNS to the effectors (muscles and glands)

C) Glial Cells of the CNS

1) General:

a) ‘nerve glue’

b) _________________

c) _________________

d) Smaller

e) Provide scaffolding/framework for neurons

2) _________________

a) about ½ of nervous tissue

b) _________________________ Forms a living barrier between

neurons and the blood capillaries

c) Function: Controls the chemical environment of neuron

3) _________________

a) _________________ clean up dead cells and bacteria


4) _________________

a) Line spaces within CNS

b) _________________________ circulate CSF

5) _________________

a) Extensions form myelin sheaths wrap around CNS axons

b) _________________ nervous impulses

D) Glial cells of the PNS: _________________

a) form _________________ sheathes of the PNS

b) Speed up nervous impulses

Section 3 Action Potential

A) 2 Main functional properties of neurons:

1) __________________ ability to respond to a stimulus

2) __________________ ability to transmit a nervous impulse to another cell

B) ___________________ an electrical event (impulse) when a stimulus of sufficient intensity is applied to a

neuron allowing sodium ions to move into the cell reversing polarity.

C) Overview of an Impulse:

1) Resting Potential

2) Stimulus

3) Threshold

4) Depolarization

5) Repolarization

6) Refractory Period

D) _________________ describes a neuron at rest, not

generating a nervous impulse

1) Extra cellular environment: _________________

a) Na+

2) Cytoplasm: _________________

a) Negatively charged proteins

b) Few K+

(potassium ions)

3) Due to difference in charge across the membrane it is described as _________________

4) Membrane is _________________ to Na+, K

+ and proteins.

E) ___________________ a minimum amount of a stimulus required to

generate an action potential.

1) Chemical: ___________________ neurotransmitters, smell, taste,

pain

2) ___________________ heat, light, pressure, vibration, stretch

3) Each membrane is sensitive (specific receptors) to specific stimuli


F) __________________

1) voltage gated channel proteins open

2) ___________________

3) Decreases charge difference over the membrane

G) ___________________ change in polarity causes the adjacent

membrane to depolarize moving along the length of the axon

H) ___________________

1) voltage gated channel proteins open

2) ___________________

3) Restores the charge difference across the membrane

4) Continues along the length of the membrane

I) At the end of repolarization

1) ___________________ extracellular environment

2) ___________________ cytoplasm

3) Neuron ___________________ generate another action potential/impulse until the membrane returns

to resting potential.

J) ___________________ period when the neuron returns

the ions to initial resting concentrations.

1) ___________________ active transport protein

2) Requires ___________________

3) Transports ___________________ INTO the cytoplasm

4) Transports ___________________ OUT of the cell

5) At the end of the refractory period, the neuron may respond to

another stimulus and generate another impulse/action potential.

K) We can measure the charge difference across the membrane during

an action potential.


L) Myelinated vs. Nonmyelinated _____________.

1) Nonmyelinated

a) AP travels the length of the axon

b) _____________

2) Myelinated

a) AP jumps from Node of Ranvier to Node of

Ranvier

b) Faster conduction of the impulse

c) ___________

Section 4 The Synapse & Neurotransmitters

A) Junction/ space formed between two neurons

1) pre-synaptic neuron: _____________________

2) Post-synaptic neuron: _____________________

B) Pre-synaptic neuron

1) Releases neurotransmitters by ____________________

2) Neurotransmitters move through the synapse by _____________

C) Neurotransmitters

1) >50 different kinds have been identified

a) _____________________ reduce perception of pain/stress

(‘runners high’)

b) _____________________ ‘message’ to skeletal muscles to

contract

2) Effect of neurotransmitter on post-synaptic neuron

a) _____________________ move the neuron closer to threshold

b) _____________________ move the neuron away from threshold

c) _____________________ between excitatory/inhibitory neurons determines whether the post-

synaptic neuron reaches threshold

3) Fate of neurotransmitter in synapse

a) _____________________

b) _____________________ returned to pre-synaptic neuron and re-used

D) Conductive cells: cells that can generate an AP

1) _____________________

2) _____________________ when ACh binds the ACh receptors on the sarcolemma, causes SR to release

Ca2+

along the entire length of the fiber

3) ‘all or none’ either the cell generates an AP or it doesn’t

4) ‘all or none’ either the muscle cell contracts or it doesn’t


Section 5 Central Nervous System (CNS)

A) Organs:

1) _____________________ (largest/most complex)

2) _____________________

3) Located within the _____________________

a) Cranial cavity

b) Vertebral cavity

B) Protection

1) Enclosed by bone

a) _________________

b) _________________

2) Meninges

a) _________________ tough fibrous CT/folds inward into fissures

b) _________________ weblike/filled with CSF

c) _________________ innermost/delicate covers the surface

d) _________________ inflammation of the meninges

3) Cerebrospinal Fluid (CSF)

a) Composition

(1) Similar to _______________ (watery broth)

(2) Fewer proteins

(3) Unique ion concentrations

(4) More vitamin C

(5) No blood cells

b) Produced by the _______________ (capillary network)

c) Fills spaces: Arachnoid mater, ventricles, central canal

d) Function: _______________

4) Blood Brain Barrier

a) _____________________ living barrier between the blood vessels and neurons

b) Neurons do NOT tolerate fluctuations of internal environment

c) Blood capillaries are the LEAST permeable in the entire body (tight junctions).

d) _____________________ Substances: Water, essential amino acids, Glucose

e) _____________________ substances: Wastes products (urea), toxins, most drugs, Proteins, Cells

and K+

f) No effect on lipid soluble substances: respiratory gases, nicotine, alcohol, anesthetics

(lidocaine/propofol/ chloroform)


C) Brain

1) _____________________ (Cerebral Hemispheres)

a) Structure:

(1) Cerebral cortex: outer gray matter

(2) Cerebral medulla: inner white matter

(3) Cerebral gyri (bumps) increase surface area/# neurons for processing/integration

(4) Cerebral sulci (grooves)

(5) Lobes named after cranial bones

(6) Longitudinal fissure separates right and left cerebral hemispheres

(7) Corpus callosum: tract of white matter connecting cerebral hemispheres

(8) _____________________ islands of gray matter

b) Function: _____________________

(1) Learning, memory, emotions

(2) Integration/processing sensory information

2) _____________________

(1) Relay sensory information to cerebral cortex

(2) Relay motor information to basal nuclei

(3) Involved in memory

3) _____________________

(1) Directly linked to pituitary gland by the infundibulum

(2) Function: important in _____________________

(a) _____________________: water balance, temperature

(b) Part of the _____________________ (emotional-visceral brain): thirst, hunger, sex, pain,

pleasure

(c) Produces _____________________

(Anti-Diuretic Hormone and oxytocin)

4) _____________________

(1) Structure: deep within cerebrum

(2) Function:

(a) mediates emotional responses

(b) Links _____________________to emotions/events

(c) Blends _____________________

(d) Involved in memory processing

5) _____________________

(1) Structure:

(a) Outer gray matter

(b) Arbor vitae: inner white matter

(2) Function:

(a) Ensures _____________________body movements

(b) _____________________ new motor skills

(c) Monitors body _____________________

(3) Directly affected by alcohol/damage


6) _____________________

(1) General

(a) ascending/sensory tracts

(b) Descending/motor tracts

(c) Pathways _____________________ carrying information to different sides for processing

(d) _____________________ information between different areas

(e) Many _____________________ (macroscopic) rigedly programmed with autonomic

behaviors

b) _____________________

(1) relay information

(2) Visual/auditory reflex centers

c) _____________________

(1) relays information between cerebrum and cerebellum

(2) Respiratory center (nuclei)

d) _____________________

(1) Relays sensory information

(2) Nuclei: heart rate, blood vessel diameter, respiratory rate, vomiting, etc.

e) _____________________

(1) Structure: system of neurons running through cerebellum, cerebrum and extending into

brainstem

(2) Function:

(a) _____________________ cerebrum/alert

(b) _____________________ unnecessary/repetitive information/stimuli

D) _____________________

1) Structure

a) About 17 inches long

b) Continuation of brain stem

c) Ascending/descending tracts

d) Central canal: CSF circulated by ependymal cells

e) Gray and white matter

f) _____________________ ‘horses tail’ terminates with spinal nerves

2) _____________________

a) Bone

b) Meninges

c) CSF


E) _____________________ : rapid, predictable, involuntary response to a stimulus

1) Always follows the same pattern

2) _____________________ stimulate skeletal muscles (example: hot stove)

3) _____________________ stimulate cardiac/smooth muscle and glands

(example: photopupillary response, blood vessel diameter, saliva secretion0

4) 3-neuron reflex arc most common

a) _____________________: light, pressure, sound, CO2 of sufficient intensity

b) _____________________: responds to a change in a stimulus (threshold) and sends that

information to CNS for processing as an action potential

c) _____________________: CNS neurons that process/integrate incoming information and

determine an appropriate response issuing the order (response) as an AP to the motor neuron.

d) _____________________: carries the order as an AP to the effector cell(s).

e) _____________________: muscle contraction or a gland secretes

Section 6 Peripheral Nervous System

A) Components

1) ___________________________ groups of nerve fibers/processes extend from the CNS

2) ___________________________ groups of neuron cell bodies outside of the CNS

B) Types of Nerves

1) ___________________________ groups of axons/processes that transmit sensory information TO CNS

2) ___________________________groups of axons/processes that transmit motor information

(commands) to effectors

3) ___________________________ groups of axons/processes that transmit sensory and motor

information

C) ___________________________

1) 12 pair extend from the brain

2) Primarily serve the head and neck

3) Include sensory nerves

a) ___________________________ vision

b) ___________________________ olfaction

c) ___________________________ hearing

4) Mixed nerves _________________


D) ___________________________ axons/processes that extend from the spinal cord

1) emerge as either sensory/motor

2) merge into mixed nerve

3) _________________ complex nerve networks that

serve limbs

a) example: cervical, brachial, lumbar, sacral plexus

E) Somatic Nervous system

1) Include motor neurons that release that stimulate

skeletal muscles (effectors)

2) Neurotransmitter: ____________

F) Autonomic Nervous System

1) Automatic control/maintains internal environment

2) Effectors:

a) __________________________ (heart rate)

b) __________________________ (digestion/BV diameter)

c) __________________________ (secretions)

3) Subdivisions include: Sympathetic and Parasympathetic nervous systems

a) Affect same organs

b) Opposite effects

c) Dynamic balance—both making fine adjustments

4) _____________

a) ‘fight or flight’ (Emergency/excited/embarassment)

b) Chemical Messenger_____________

c) Hormones widespread/prolonged effects (‘come down’)

d) Characteristics:

(1) inhibit tears, digestion, urination

(2) dilate pupils, bronchi

(3) increase heart rate

(4) stimulate adrenal gland

5) _____________

a) Rest/conserving energy—digestion/defecation/diuresis

b) Chemical Messenger: _____________

c) Characteristics:

(1) Stimulate tears, digestion, urination

(2) constrict pupils, bronchi

(3) decrease heart rate

Human Biology 175 Section 1...

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