unit 7– nervous tissue & senses

Unit 7– Nervous Tissue & Senses

I. Organization of The Nervous System

A. Structural Organization of the Nervous System

Central Nervous System (_____)

CNSBrain (100 billion neurons)Spinal Cord (100 million neurons)

Peripheral Nervous System (_____) – all nervous tissue outside of CNS

PNS

12 Pairs of Cranial Nerves

31 pairs of spinal nerves Ganglia

Other nerves

Peripheral Nervous System (PNS)Sensory Receptors in skin & other places

B. Functions of the Nervous System

& Types of Neurons that help with Nervous

System Functions:

1. _____________________ different types of stimuli from internal

and external environment. This is

done by:a. ______________________- neurons that carry

sensory information from nerves

to the CNS or from a lower to a higher level in the CNS

Senses

Afferent Neurons

2. _____________________ information by analyzing and storing some of it. This is done by:a. ____________________ - nerve cells whose axons extend for a short distance and contact nearby neurons in the brain, spinal cord or ganglia.i. Interneurons comprise the ________________ of neurons in the body.

Integrates

Interneurons

majority

3. _________________ response to integrative decisions via carrying messages from the brain or spinal cord to effector cells and organs. This is done by:a. ________________________- nerve cells that carry information from the brain toward the spinal cord or out of the CNS into the spinal & cranial nerves. These neurons make contact with:

Motor

Efferent Neurons

i. __________________________ - cells and organs that respond to the neural impulse sent by the efferent neurons (skeletal muscle fibers, cells in glands, etc).

Effectors

C. Functional Organization of the Nervous System

1. CNS Functional “jobs”:a. Integrates many different

kinds of _____________ information.b. The source of _______________, emotions & _______________________.

sensorythought

memories

2. PNS:a. Functional organizational “jobs”: i. Gather information from ______________ & external environment to send to CNS via ____________________. ii. Sends response from the CNS via ___________________________.

b. Further subdivisions of the PNS based on ________________ or involuntary control & the type of ____________________ provoked.

Internal

Afferent Neurons

motor neurons

voluntaryresponse

Somatic Nervous System (SNS): under__________________Voluntary Control

#1 - Somatic sensory ___________ receive information from the head, body wall, limbs, vision, hearing, taste, touch & smell.

receptors

#2 – Information is sent to the _______CNS

#3 - Sensory motor ___________ send impulses to _____________ muscles ONLY.

neurons

skeletal

Autonomic Nervous System (SNS): under__________________

Involuntary Control

#1 - ________ sensory receptors receive information from the visceral organs (stomach, lungs, etc).

Autonomic #2 – Information is sent to the _______CNS

#3 - __________________________ of autonomic motor division responds if an emergency or exercise action is provoked. (______________________)

Sympathetic Division

“fight or flight” response

OR #3 - __________________________ of autonomic motor division responds if a need to relax and slow down is provoked. (______________________)

Parasympathetic Division

“rest & digest” response

A. Two Type of Cells1. _____________ - nerve cells

which are for information processing & conducting nerve impulses.

a. Three functional types:i. _____________________ii._____________________iii._____________________

II. Nervous TissueNeurons

Afferent neuronsInterneuronsEfferent neurons

Cell body

Dendrite

Axon

hillock

Myelin Sheath

Schwann Cell

Nodes of Ranvier

Synaptic Bulb

Axon Terminal

b. Anatomy of the Neuron

Synaptic Vesicle

1. Cell body – contains the __________ & ______________ (golgi, ER, lysosomes & mitochondria)

2. Dendrites – receives the ___________, along w/ the cell body.

3. Hillock – area between the __________ body & ____________.

4. Axon - _________ the nerve impulse along the cell toward the axon __________.

nucleusorganelles

signal

cellaxon

conducts termina

l

5. Nodes of Ranvier – _______ in the myelin sheath which nerve impulses jump between.

6. Axon Terminal – the _____ of the axon

7. Mylelin Sheath – layers of lipids & proteins that surround the axons of most neurons to _______ up the transmission of nerve impulses. (neurons with a myelin sheath are said to be ___________. Those without are ________________.)

8. Schwann Cell - __________ that produces the ________ sheath.

gaps

end

speed

myelinatedunmyelinated

neurogliamyelin

9. Synaptic Bulb – __________ at the end of the axon terminal that contains the synaptic vesicles.

10. ______________________ - contain neurotransmitter.

11. _______________________ - space between the axon terminal and another neuron (or effector cell).

Synaptic Vesicles

Synapse

swelling

2. _______________ - cells that support, nourish & protect the neurons. They __________ homeostasis in the interstitial fluid that ___________ the neurons.

a. Brain tumors derived from neuroglia are called_________ (often highly malignant

& fast growing).

Neuroglia

maintainbathe

gliomas

b. Types of Neurogliai. ______________ - provides nutrients &

necessary chemicals for nerve impulses to the neurons of the CNS and help form the _________-___________ barrier.

Astrocytes

Blood brain

ii. ___________________ - supports the ______ neurons and create their __________ __________.

OligodendrocytesCNS Myelin sheath

iii. _________________ - supports _____ neurons by creating their _________ sheath.

Schwann Cells PNSmyelin

iv. _________________ - engulf microbes that invade the ________ and clear away _____________ of dead cells.

MicrogliaCNS

debris

III. Neuron CommunicationA. Function of Plasma Membrane in neural

communication:1. A neuron’s plasma membrane (like many body cell’s ) exhibit a ___________________ ________________- a difference in the amount of electrical charge on the inside of the cell as compared to the outside of the cell (like stored voltage in a battery.)

membrane potential

a. electrical charge is due to the flow of _________ which is caused by the presences of two things in the plasma membrane:

i. _______________ - allows passive diffusion of specific ions to move down their concentration gradient. (ie- there are K+ ion specific channels and Na+ ion specific channels).

ions

Ion channels

Na+

Na+Na+

Na+

Na+

K+K+

K+K+

K+

Extracellular Fluid

ii. ____________________- Using one ________ molecule, the Na+/K+ pump ACTIVELY sends ______ Na+ ions out of cell & _____ K+ ions into the cell to restore original balance.

Na+/K+ pump ATP3

2

B. _____________________________- the voltage difference between the inside and outside of the cell membrane when the cell is NOT responding to a stimulus. 1. What is the measurement of the voltage difference?a. __________________ - (the minus sign indicates that the INSIDE of the cell is negative relative to the outside of the cell.)

Resting Membrane Potential

- 70 millivolts (mV)

2. What causes this voltage difference?a. NEGATIVELY charged _______________ & _____________________ are stuck inside the cell (cannot diffuse passively) and POSITIVELY charged______________ do not EASILY move into the cell (b/c many of their ion channels are CLOSED).

proteinsPhosphate ions

Sodium ions

- 70 mv

C. ___________________________- an electrical signal that propogates along the membrane of a neuron. (also called a_______________________).

Animation of an Action Potential: http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter14/animation__the_nerve_impulse.html

Action Potential

Nerve impulse

Step #1:______________________________ a. ___________ - an action which changes the permeability of the neuron’s cell membrane by causing ______ ion channels of a

neuron’s ______________ to open, allowing Na to rush __________ the neuron. (examples of a stimulus – touch, pressure, olfactory particles, gustation particles, neurotransmitters, vibrations, light, etc)

Stimulus Detectionstimulus

Na+dendriteINTO

1. Seven Steps of An Action Potential

STIMULUS

STEP #2:___________________________________a. When Na+ rush into the cell, the membrane potential becomes more ____________________ (it _____________________).

Depolarizing the Membrane

Positivedepolarizes

Step #3:___________________________________a. ______________________ - when the membrane potential depolarizes to __________, and an action potential carries through the length of the neuron. b. If the neuron’s membrane does NOT

depolarize to _____________, an action potential will not carry through the

length of the neuron.

Reaching Thresholdthreshold

-55 mV

-55 mV

Step #4: ___________________________________

a. MANY Na+ ion channels open and Na+ rushes __________ the cell even ____________ until the membrane potential reaches ________. (~20,000 Na+ ions rush in)

into FASTER

+30 mV

Depolarization Phase of An Action Potential

Step #5: ____________________________________

a. when +30 mV is reached, the Na+ ion channels close and ________ ion channels are now open so K+ rushes ______ of the cell by ______________.

Repolarization Phase of An Action Potential

K+out diffusion

Step #6:____________________________________

a. When K+ ions rush out of cell, the membrane potential dramatically __________________

and goes________________-70 mV.

decreases

Hyperpolarization phase of an Action Potential

below

Step #7:____________________________________

a. Because Na+ and K+ are both in the __________ place, the ________ pump uses

ATP to actively transport that Na+ back _____ of the cell and K+ back _______ the cell to return to ____________________________b. At this time, _____ new action potential.

Refractory Period of An Action Potential

NO

wrong Na+/K+out

intoResting membrane potential

2. How does an action potential travel down the length of a neuron and move from one neuron to the next?a. Once the hillock of the neuron reaches _____________, steps ___________ continue to happen & the action spreads down the ____________ of the neuron like knocking over dominoes. An action potential in one area causes the part of the axon next to it to __________________ to threshold.

threshold

axon

depolarize

4-7

#2 - STIMULUS

#3 - THRESHOLD

#4 - Depolarization

#5 - Repolarization

#6 & 7- Hyperpolarization & Refractory Period

#1 - Resting Membrane Potential

3. Graph depicting the quantitative steps of an Action Potential

4. All-or-None Principle of Action Potentials:a. as long as a stimulus is _______________ enough, an action potential will always occur.b. a much stronger stimulus _____________ cause a larger action potential b/c the magnitude of the action potential is always the __________.

c. a weak stimulus that does not reach threshold will _________ create an action potential.

strong

CANNOT

same

NOT

D. Two Kinds of Conduction1. _________________________-the action potential spreads along the entire axon until the axon terminal is reached.i. used by _____________________ neurons ii. The conduction travels relatively ___________.iii. Unmyelinated neurons are typically

found in the _________ b/c these neurons don’t have to travel long distances.

Continuous Conduction

unmyelinated

slowly

CNS

2. _____________________________-the action potential _____________from node of Ranvier to

node of Ranvier.i. used by __________________ neurons.ii. Much ________ than continuous conduction.iii. Found in neurons of the _______

(sensory & _________ neurons).

Saltatory Conductionjumps

myelinatedfaster

PNSmotor

E. Factors besides myelination that affect the rate of nerve conduction:1. ________________ - wider is faster (same as in electrical wire)2. _______________ - hotter is faster (This is why ________ reduces pain)

Video of continuous vs. saltatory conduction http://ttc.depere.k12.wi.us/SafeVideos/Video.aspx?id=DJe3_3XsBOg

Axon width

Temperatureice

G. ___________________________- a series of events that occur at the synapse in order for one neuron to communicate with another.1. Terms to understand with synaptic transmission.a. _____________________- the neuron sending the signal.b. _____________________- the neuron receiving the signal.

Synaptic Transmission

Presynaptic neuron

Postsynaptic neuron

c. ________________________- chemical stored in the synpatic cleft in response to a nerve impulse & changes the membrane potential of the postsynaptic neuron.

neurotransmitter

2. STEPS OF A SYNAPTIC TRANSMISSION

#1 - Presynaptic neuron fires __________ and sends the signal to the ____________________ neuron.

#2. The action potential reaches the _______________ and causes the synaptic __________________ in the presynaptic bulb to _______________ their ______________________ into the synaptic _________ between the two neurons.

firstpostsynaptic

axon terminalvesicles

release neurotransmittercleft

#3. The neurotransmitter ______________ across the space and joins to receptors on the postsynaptic neuron, which causes ion channels to _______ there.(two different outcomes can result)

i. ____________________ - the neurotransmitter causes the

postsynaptic neuron to depolarize and possibly

produce an action potential if it’s hillock

reaches ______________.

diffuses

open

Excitatory Effects

threshold

Diagram of an Excitatory Effect

ii. ____________________-the neurotransmitter can cause the postsynaptic neuron to hyperpolarize and prevent it from reaching

threshold & firing.

Inhibitory Effects

3. Different types of neurotransmitters and their function:a. ________________________- excitatory neurotransmitter that plays a role in awakening from a deep sleep.

b. _______________________- excitatory neurotransmitter used in the synapses of _____________ to make them contract.

Acetylcholine

muscles

Norepinephrine

c. ________________ - special neurotransmitter because it is considered to be both excitatory and inhibitory that helps with depression, memory focus & even muscle tone.

Dopamine

d. _______________- inhibitory neurotransmitter that is involved in sensory perception, temperature regulation, mood, appetite & onset of sleepiness. (eating carbs _____________ the release of seratonin).

i. ____________________- antidepressent

drug that blocks the uptake of seratonin.

Seratonin

increases

prozac

e. ________________ - inhibitory neurotransmitter considered to be natural painkillers released during times of body stress. (linked to improved __________, learning & feelings of euphoria)

Endorphin

memory

4. When the neurotransmitter is _____________ from its receptor, its effects are ___________. (This can happen 3 ways.)a. destruction by __________________.b. ______________ - actively transported back into the neuron using ATP.c. Uptake – actively transported into _______________.

removedstopped

enzymesReuptake

neuroglia

5. Common disorders related to neurotranmitters and nerve conduction:a. __________________________- complex mental disorder that makes it difficult to tell the difference between real and unreal experiences that can be due to accumulation of excess ___________________.

Schizophrenia

dopamine

b. ________________________- an autoimmune disease caused by the progressive degeneration of myelin sheath of the CNS neurons that results in progressive loss of motor function.

c. ______________ - a neural disorder characterized by short attacks of motor, sensory & psychological malfunction due to abnormal firings of the neurons.

Multiple sclerosis (MS)

Epilepsy

d. _________________________- a progressive nervous disease that leads to muscle tremors, slowing of movement, & facial paralysis that causes the destruction neurons that produce dopamine.

Parkinson’s Disease

A. Basic Facts of the Brain1. It contains:

a. ________________ neuronsb. ________________ neuroglia

(“Fun Fact” – It weighs about 3 pounds)

100 billion 10-50 trillion(500,000 times more)

IV. The Brain

B. Main Protective Coverings of the Brain:1. _____________________2. ____________________- layers of connective tissue (collagen & elastic fibers) surrounding the brain and spinal cord.

cranium meninges

a. The three sub-layers of the meninges are:i. _________________ - outer TOUGH layer. (Hint – it is “dura”ble)ii. __________________ - middle layer. Looks like spider webs. iii. _______________ - very thin inner layer that contains NUMEROUS blood capillaries.

Dura Mater

Arachnoid Mater

Pia Mater

Arachnoid mater

C.______________________________- a system of tight cell junctions in between the epithelial tissue of the meninges that prevents the blood from DIRECTLY entering into the brain.

Blood-Brain Barrier

1. Why is it important to have the blood- brain barrier?

a. it protects the brains cells from __________________ and other

________________________ that might

be in the blood.

pathogens harmful substances

2. Even though the brain does NOT come in direct contact with blood, it require a constant _______________ supply because:a. If the blood flow to the brain stops even briefly, ______________________ will result.

b. If brain neurons are deprived of oxygen for more than ________________ minutes, they will be permanently injured.

c. The brain does not store _________, so it needs a continuous supply or dizziness, ____________________, convulsions and/or loss of consciousness results (these are typical symptoms of the hypoglycemia effect of diabetes).

blood

unconsciousness

4

glucose confusion

3. So if blood can’t directly enter the interstitial fluid of the brain, what is able to help perform this function?

a. ______________________________Cerebrospinal fluid

D. Cerebrospinal fluid = - clear,__________________ fluid that does not contain ANY blood cells in it (basically “matrix” only).1. Where is it found?a. ____________________- space between the arachnoid mater and the pia mater.b. ___________________- cavities located inside the brain that collect the cerebralspinal fluid (there are 4 of them).

colorless

Subarachnoid space

Ventricles

2. How is cerebrospinal fluid made?a. It is made from ______________________ being filtered into the subarachnoid space.

Blood plasma

3. Functions of the cerebrospinal fluid in the brain:

a. Provides a constant supply of nutrients,

specifically ________________ & __________________ to the brain.

b. Transport waste from _______________ to

blood.

Glucoseoxygen

brain

Nerve Cells

Carries nutrients

Transports waste to blood

4. Ailment relating to cerebrospinal fluid:a. _____________________- when the cerebrospinal fluid does not get reabsorbed into the blood vessels as fast as it gets formed and it can cause rising ________________ & swelling of the ____________________. pressure

brain

hydrocephalus

AS WE BEGIN OUR STUDY OF THE FUNCTIONS OF THE DIFFERENT PARTS OF THE BRAIN REMEMBER………..

Most of what has been learned is via damage to “that” part of the brain and learning what functions were lost.

E. Four Major Parts of the Brain

________________ - Outer part of the brain (detailed later).

Cerebrum

_________________- a. receives input from sensory receptors, spinal cord and other parts of the brain to produce _______________ coordinated muscular movements. b. Stores all __________ motor activity (like catching a ball). c. Regulates _________ and balance.

Cerebellum

posture

SMOOTH

skilled

_________ - continuous with the spinal cord (detailed later).

Brain Stem

______________- in the center of the brain (detailed later).

Diencephalon

Midbrain (~32)Pons (36)

Medulla Oblongata (39)

F. Parts of the Brain Stem:

G. Functions of the Parts of the Brain Stem:1. MIDBRAIN – major part of neural

______________ for: a. Pupillary _____________

b. Vision _____________ & scanning

c. Vision ___________________ reflex

(for continued focusing).d. ____________ reflex. e. ________________ pathway.

.

PATHWAY

reflex

Accommodation

startle Auditory

tracking

2. PONS- acts like a _______________ that connects parts of the brain (via bundles of axons) with one another, specifically, it connects:

a. the ______________________ to ______________________ to help

coordinate voluntary movements.b. the ______________ & _______________

sides of the cerebellum.

BRIDGE

cerebrum cerebellum

right left

3. Medulla Oblongata – the _______________ center because it contains the:a. ___________________________________ - regulates the rate & force of the ____________________

b. _______________________________ – regulates breathing rate. (Extra fact – The Medulla Oblongata is right around C1-C2, which is why a broken neck to this area is most certainly fatal).i. because of this, also controls “airway-like” reflexes – (_____________________________ ______________________)

Medullary Rhythmicity Areaheartbeat

Cardiovascular Center

“RATE”

swallowing, sneezing, coughing, vomiting

Hypothalamus(21)

Pineal Gland (23)

Thalamus(26a, 19, 20)

H. Parts of the Diencephalon

PituitaryGland (25)

Not really part of the diencephalon but VERY closely connected to the hypothalamus

I. FUNCTIONS OF THE Parts of the Diencephalon1. THALAMUS – sensory __________________ of the brain.a. Receives input from all types of ____________ receptors (ex-sight, sound, touch, taste, smell) and determines what sensory information is _____________ to send on to other parts of the brain.

“FILTER-ER”

sensory

worthy

2. HYPOTHALAMUS - a. Helps to regulate many __________________ functions (heart rate, movement of food through the digestive tract, urinary bladder contraction)b. controls the release of hormones of the _____________________ gland which regulates many emotional & behavior patterns (rage, aggression, pain, pleasure, hunger, thirst, body temperature)

c. Regulates the body’s __________________________ - ( awake and sleep patterns).

autonomic

Pituitary (25)

circadian rhythm

3. PINEAL GLAND - produces ________________ which promotes sleepiness & helps set the body’s biological ______________. (this is really part of the endocrine system b/c it secretes a hormone)

melatonin

clock

Gyrus (folds)

Sulcus (shallow grooves)

Gray Matter (unmyelinated bundles of axons)

J. Cerebrum1. Anatomical Parts of the

Cerebrum

Cer

ebra

l C

orte

x

white matter(myelinated bundles of axons

Fissure (DEEP grooves)

_______________________- Divides the brain into right & left halves

______ hemisphere – (the “SEQUENTIAL SIDE”) controls language, speaking, math, logical operations & processing sequence information.

Longitudinal Fissure

Left

______ hemisphere – (the “SENSITIVE SIDE”) controls patterns & face recognition, nonverbal processing & emotions.

Right

___ ________________________ - white matter that connects the 2 hemispheres of the cerebrum.

Corpus Collosum (10)

2. ________________ of the Cerebrum & their associated functions:

motivation, personality, ___________ thought, memory & initiates movement.

Four Lobes

Speech

Sense of touch, reading, speech & _______________. taste

vision

Hearing & smell

K. Memory & Learning 1. What happens when learning occurs?

a. __________________ of existing nerve

connections.b. ____________ of new connections.

strengthening

growth

2. What are different types of memories and where are each stored?a. ________________________- i. storage time is in the order of __________________.ii. It is stored in the _____________ lobe.iii. It seems to be able to hold _______________ items. (This is why phone numbers are 7 digits long)

SHORT TERM MEMORY TESThttp://faculty.washington.edu/chudler/stm0.html

Short-term MemorySeconds (20-30 sec)

frontal7 +2

b. ________________________ i. storage time can be minutes, hours, ____________ or years, depending on ______________ of recall demands.ii. It is stored in the ____________________ (diagram to follow).iii. The amount of material that can be held is potentially _____________________.

Long Term Memorydays

frequency

hippocampus

limitless

Hippocampus

3. What are ways to help short-term memories become long-term memories (transferring from frontal lobe to hippocampus)?a. _________________ the material wanting to be stored.

b. Associate the material with ______________________ (they can be positive or negative emotions).

c. ________________ the material with previously learned information.

d. Create ______________ & ___________________ when learning the material.

Repeating

Strong emotions

Linking It

Patterns Visual Images