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74 Cards in this Set

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DEPOLARIZATION
ABSOLUTE REFRACTORY PERIOD
-70 signal
-55 threshold
+30 Action potential
1. Recives end plate potential
2. Sarcolomma becomes permeable to sodium
3. Voltage gated channels open
4. Sodium diffuses rapidly into cell
5. Resting potential decreased (Inside becomes more positive)= DEPOLARIZATION
6. If stimulus reaches threshold action potential occurs
Action potential travels over the entire sarcolomma

Second step in Action Potential
1. Positive charge resulting from open sodium channels
2. Membrane potential in that region decreases
3. Depolarization occurs in that region too
REPOLARIZATION
Electrical conditions restored
+30
RELATIVE REFRACTORY PERIOD

Third step in Action potential
1. Depolarization wave passes
2. Sodium channels close
3. Potassium channels open
4. Potassium diffuses from cell
5. Internal negativity is restored
Refractory Period
Cell cannot be stimulated again until repolarization is complete.Keeps us from unwanted repeated movements
Resting Membrane Potential
-70
Called end plate potential
-55
Threshold

Strong enough signal
Below -55 no action
Longitudinal Fissure

Transverse Fissure
Separates the cerebral hemispheres

Seperates the cerebral hemishperes from the cerebellum
ATP Sodium/ Potassium Pump
Restores ionic conditions of the resting state

3 sodiums pumped out
2 potassiums pumped out
ACh
Acetylcholine
Causes ion channels to open

def: Neurotransmitter
fx: Opens ion channels and initatating depolarization
1. Diffuses into synaptic cleft
2. Attaches to sarcolomma receptors
3. Open ion channels
4. Initiates depolarization
First step excitation-contraction coupling
Transmission/ transportation of action potential
1
1.Action potential propagates along sarcolomma
2. Goes down T-tubules
After action potential travels through the T tubule

Second step excitation- contratraction coupling

2
1. Action potential in T tubule activates voltage sensitive receptors and triggers Calcium release from the terminal cisternae of SR into cytosol
Calcium binds to this

Third step excitation-contraction coupling

3
1.Calcium binds to troponin
2. Troponin changes shape
3. Removes the blocking action of tropomyosin
4. Actin active sites exposed
Myosin heads do this

Fourth step excitation-contraction coupling

4
Contraction
1. Myosin heads attach to actin
2. Myosin heads detach
3. Pull actin filaments toward the center of sarcomer
4. Release of ATP hydrolysis(Powers the stroke/cycling process)
Calcium pump does this

Fifth step excitation-contraction coupling

5
1. Action potential ends
2. Calcium removed ATP calcium pump
3. Calcium put back into the SR (Sarcoplasmic Reticulum)to be stored
Low levels of calcium that are needed to bind troponin make this occur

Sixth step excitation-contraction coupling

6
1. Tropomyosin blockage restored
2. Myosin blocked from binding on sites of actin
3. Contraction ends(crossbridge activity)
4. Muscle fiber relaxes
Tropomyosin
Does this to myosin

Block myosin binding sites on actin so that the myosin heads cannot bind to actin.
Troponin
Calcium binds to this

Calcium binds to troponin, which changes shape and removes the blockin action of tropomyosin.
Hyperpolarization

Keeps nerve impulses from probability (reaching threshold)
Below -70
Membrane potential increases
Becomes more negative inside
than in resting potential
-70mV to -75mV
Nerve impulses need to be stronger to reach threshold in hyperpolarization.
Central Nervous System

Interprets sensory input and dictates motor responses based on past experiences
Composed of:
brain and spinal cord

fx: integrating and command center of the nervous system
Brain Development

Starts in a 3 week embryo
Surface ectoderm develops into
Nerual plate
Neural folds
Neural groove
Neural crest
Neural tube
Cerebrum

Lateral ventricles
Formed from: Telencephalon
Make up:
Cerebral Hemispheres which are:
Cortex
White matter
basal nuclei
Diencephalon

Third ventricle
Formed from: Diencephalon
Make up:
Thalaumus
Hypothalamus
Epithalimus
Retina
Brain Stem 1

Cerebral aqueduct
Formed from: Mesencephalon
Midbrain
Brain Stem 2

Fourth ventricle
Formed from: Mesencephalon
Pons
Brain Stem 3

Fourth ventricle
Formed from: Mesencephalon
Medulla oblongata
Cerebral Cortex

CONSCIOUS MIND
Part of the cerebral hemisphere

1.Enables us to be aware of ourselves and our sensations
2.Communicate
3.Remember
4.Understand
5.Initiate Voluntary Movements

Composed of: gray matter, neuron cell bodies, dindrites, associated glia, blood vessels -NO fiber tracts
Diencephalon
Formed from: Diencephalon
Make up:
Thalaumus
Hypothalamus
Epithalimus
Retina
Third ventricle
Primary Motor Cortex
loc: posterior part of frontal lobes

Allows conscious control of precise, skilled, voluntary movement
Premotor Cortex
Contorls learned, repititous, or patterned motor skills.

Planning of movement
Broca's area:
Present in only one hemisphere(left)
Motor speech area: directs the muscles involved in speech production
Frontal eye field
Gives us the ability to move the eyes.
Somatosensory:

Somasensory Association Cortex
Stimulus goes in

Integration(forming the comprehensive)
Prefrontal cortex:

Wernicke's Area:

Left brain:

Right brain:
Personality (frontal labotomy)

Words you don't know

language, math, logic

Spacial skills, emotion, artistic skills
What is cerebral White Matter

MUST HAVE LINKS IN ORDER TO COMMUNICATE
loc: deep to the cortical gray matter

contains: basal nuclei
fx: responsible for communication between cerebral areas and
1. cerbral cortes
2. lower CNS centers
3. the rest of the brain
Basal Nuclei

sometimes called basal ganglia
loc: deep within the cerebral white matter

contains:
Caudate
Putamen
Globus pallidus

corpus striatum

fx:
1. Influence muscle movements directed by the primary motor cortex
2. Inhibit antagonistic or unnecessary movements

Disorders: To much or too little movement Hunington's chorea and Parkinson's disease
Gyri plural
Gyrus singular
Loc: top of cerebral hemishphere, top of cortex
def: elevated ridges of tissue (twisters)
Sulci plural
Sulci singular
Loc: cerebral hemisphere
def: shallow grooves in brain
several sulci divide each hemisphere into five lobes

Divide the cerebral hemispheres into lobes
Central Sulcus
Loc: frontal plane
fx: seperates the frontal lobe from the parietal lobe

Divide frontal and parietal lobes
Parieto- Occipital Sulcus
Loc: on the medial surface of the hemisphere
fx: seperates occipital lobe from parietal lobe

Divide occipital and parietal lobes
Lateral Sulcus
Loc:outlines the temporal lobe
fx: separates the parietal and temporal lobes
contains: insula

Deep sulcus divides parietal and temporal lobes
PNS
Peripheral Nervous System
Paired spinal and cranial nerves
fx: carries messages to and from the brain and spinal cord
MESSENGER
Thalamus
DEEP WELL HIDDEN PROTECTED
RECEIVES FIBER FROM THE CEREBRAL CORTEX
COMMUNICATION CENTER
IT IS THE CENTER POINT

Receives input and funnels it to the cerebral cortex.
fx: key role in
1. mediating sensation
2. motor activities
3. corticol arousal
4. learning
5. memory
Hypothalamus
Connects to pituitary gland
Stalk of hypolthalamus is called the infundibulum
CONTROL CENTER (VISCERAL)

fx: main visceral control center in the body
1.maintains water balance
2.regulates thirst
3.eating behavior
4.gastrointestinal activity
5.body temperature
6.activity of the pituitary gland(secretion of hormones) and produce hormones ADH, Oxytocin
7. Sleep-Wake cycles(daylight,darkness clues)
Epithalamus
SLEEP HORMONES AND MOOD

Pineal Gland
Secretes melatonin
Anatomy of Cerebellum

Looks like a tree(arbor vitae)

HAS RIDGES
2 hemishpheres
3 lobes
Anterior
Posterior
Floccunondul
marked by convolutions
seperated by vermis
connected to brain stem by
superior, middle, inferior peduncles
Fx of Cerebellum

Takes information tells us the best way to move

PROTRUDES UNDER OCCIPITAL LOBES OF CEREBRAL HEMISPHERES
COORDINATION OF MOVEMENT
SUBCONSCIOUSLY
Processes
Interprets impulses from: 1.motor cortex
2.sensory pathways
3.coordinates motor activity
this means smooth, well timed movements
4. Cognition
Anatomy of Midbrain


Connects 3rd & 4th Ventricles
Cranial Nerves III and IV

Between diencephalon and pons
Surrounds the aqueduct
Contains:
1.Corpura Quadrigemina(visual/auditory reflex centers)
2.Red nucleus (subcortical motor centers)
3.Substantia nigra
High content of melanin pigment precursor to dopamine
4.periaqueductal grey matter (involved in pain supression)
Controls two cranial nerves
III and IV
Fx of Midbrain

Startle Reflex
Superior colliculi- Visual reflex centers: coordinate head and eye movements when we visually follow a moving object
inferior colliculi: auditory relay from the hearing receptors of the ear to sensory cortex. Startle reflex occurs here
Pons

Anterior wall of 4th Ventricle
CONDUCTION AREA
REGULATION OF RESPIRATION AND CRANIAL NERVES V-VI-VII

Between midbrain and medulla oblongata
Complete pathway between higher brain centers and spinal cord
Anatomy of Medulla Oblongata

4th Ventricle
Most inferior part of brain stem.
Central canal of the spinal cord continues upward into the medulla.
Desussation of the pyramids: Crossover causes voluntary movements of muscles on opposite side.
Hypoglossal nerves
Glossopharyngeal nerves
Vagus nerves
Vestibular nuclear complex: Maintain equilibrium
Cochlear nuclei(auditory relay)
Pyramids
Olives
Fx: Medulla Oblongata
AUTONOMIC REFLEX CENTER

Cardiovascular center:
Adjusts the force and rate of heart contraction to meet body needs
Vasomotor Center: Changes blood vessel diameter
Respiratory Centers:
Control rate and depth of breathing/ Maintain respiratory rhythm
Various other centers:
Vomiting, hiccuping, swallowin, coughing, sneezing
Peripheral Nervous System
loc: Outside the CNS

consists of:
1.Nerves(bundles of axons)that go from the brain and spinal cord
2 Spinal nerves: carry impulses to and from the spinal cord
3. Cranial nerves: carry impulses to and from the brain
PNS Sensory Afferent Division

Afferent: Carrying toward
Keeps the CNS informed of events happening in and outside of the body
consists of:
nerve fibers: convey impulses to the CNS

sensory receptors:-convey impulses from the skin, muscles, joints called SOMATIC AFFERENT FIBERS

transmit impulses from visceral organs
VISCERAL AFFERENT FIBERS
PNS Motor Efferent Division

Efferent: Carrying away
Carries impulses from CNS to effector organs (muscles/glands)
This impulse activate muscles to contract and glands to secret
Somatic Nervous System:
Impulse from CNS to Voluntary nervous system (Skeletal muscles)
fx: control our skeletal muscles
Autonomic Nervous System: (ANS)
Visceral motor nerve fibers that regulate the activity of involuntary nervous system (smooth musxles, cardiac muscles, glands)
Parasympathetic
Conserves energy
Promotes housekeeping functions during rest
Symathetic
Mobilizes body systems during activity
Supporting Cells
Anatomy of
Neurologia: Also called glia cells(nerve glue)

Distinguished by:small cell size and darker staining nuclei

Most have branching processes and a cell body

fx: cells provide a supportive scaffolding for neurons.
Astrocyes (Star Cells)
Most abundant of all glial cells.
Numerous radiating process.

1. Guiding the migration of young neorons

2.Control chemical environment by "Mopping up leaked potassium ions, recapturing/ recycling released neurotransmitters.
Microglia (Ovid cells)

Important becaus cells of the immune system are not able to acces the CNS
Thorny processes

fx: Monitor health of neurons

If finds invading microorganisms or dead neurons microglia transform into a macrophage and phagocytizes the debris.
Ependymal cells: Wrapping garment

Shape from squamos to columnar some are ciliated

Protective Barrier
fx: line the central cavities of the brain and the spinal cord.

Makes a permeable barrier between cerbrospinal fluid and tissue fluid

Cilia helps to circulate the cerebrospinal fluid that cushions the brain and spinal cord
Oligondendrocytes


Wrap CNS nerve fibers/ Myelin Sheaths
Not many processes

Wrap processes tightly around fibers, producing insulating coverings called
Myelin Sheaths
Satellite Cells
loc: surround neuron bodies in the PNS (ganglia)

fx: unknown
Schwann cells (neurolemmocytes)
Surround and form myelin sheaths aroung the larger nerve fibers in the PNS

Vital to regeneration of damaged Peripheral nerve fibers
Neurons

structural units of the nervous system
Highly specialized cells that conduct messages in the form of nerve impulses from one part of the body to another.

1. Extreme longevity (lifetime)
2. Amitotic- Do not divide they cannot be replaced
3. High metabolic rate - Always need oxygen and glucose -die within couple minutes w/out oxygen

all have cell body and one or more processes.
Dendrites
fx: Main RECEPTIVE or INPUT region of neuron

Electrical signals graded potentials- don't reach threshold

Processes in CNS called Tracts
Processes in PNS called Nerves
Short, tapring, branching extensions.(Twiglike)Cluster close to the cell body

Has a large surface area RECEIVE SIGNALS FROM OTHER NEURONS
Axon
fx: CONDUCTING REGION generates nerve impulses and transmits them away form the cell body of neuron

fx: secrete neurotransmittors

NO NISSL BODIES OR GOLGI BODIES

Some of these are very long.
Lumbar region of spine to foot (3) meters long
Every neuron has a single axon.
Axon arises from CONE shaped Axon Hillock- then becomes skinny.

ANY LONG NEURON CALLED A NERVE FIBER

Axons have OCCASIONAL branches along their length called AXON COLLATERALS AT THE END OF THE AXON
Myelin Sheath

Myelin sheath is surrounded and formed by Schwann cells in the LARGER neurons in the PNS
White, fatty(protein, lipid) segmented.

1.Protects and electrically insulates fibers
2. Increases transmission of nerve impulses
Schwann cells

ONE INTERNODE= Nucleus and most of the cytoplasm end up as a bulge just external to the myelin sheath
NEURILIMMA= Sheath of Schwann. Surround and form myelin sheaths around the larger nerve fibers in the PNS

Tightly coiled wrapped membranes.

Schwann cells do NOT touch
Nodes of Ranier (Neurofibril Nodes)

CURRENT(action potential) CAN ONLY PASS THROUGH THE MEMBRANE OF A MYELINATED SHEATH HERE!!!
def: Gaps between Schwann cells along an axon.

Occur at regular intervals along the myelinated axon- the current jumps from node to node.

Widely spaced in the CNS
Multipolar Neuron Type
Many processes all dendrites 1 single axon
Receptive region
Chemicaly gated ion channels
Interneurons and Motor neurons
Bipolar Neuron Type

Sensory neurons
Two processes
one process on dendrite
one on axon
Conducting region(generates/transmits) action potential
Voltage gated Sodium and Potassium channels
Rare.
special sensory organs
(olfactory mucosa, eye, ear)
Unipolar(psuedopolar)

Sensory neurons
Send to afferent pathways to the CNS for interpretation
One process from the cell body forms central and peripheal processes which together comprise an axon
Seretory region (release neurotransmittors)
PNS Common in dorsal root ganglia, sensory ganglia of cranial nerves