Dat: Nervous System

Front 1

Intercellular Communication is accomplished chemically via 3 molecules:

Back 1

1) Neurotransmitters---Close distances and fast-acting
2) Local Mediators---immediate around cell
3) Hormones---Far distances and slow-acting

Front 2

Local Mediators

Back 2

May be proteins, amino acid derivatives, or fatty acids (prostaglandins)
-Part of Paracrine System

Front 3

Parts of nervous system include:

Back 3

Brain, spinal cord, nerves, neural support cells, and sense organs (eye, ear, etc)

Front 4

Neuron

Back 4

Functional unit of nervous system. Highly specialized; lost capacity to divide.

Front 5

What do neurons depend entirely on for energy?

Back 5

Uses facilitated diffusion to import glucose without the need of insulin.

Requires effective aerobic respiration.

Front 6

Dendrites

Back 6

Protrude and act as antennae, sensors that receive stimuli as individual units and collectively transmit to cell body (soma).

Front 7

Axon Hillock

Back 7

Connects soma to axon and is the location where action potential is initiated in all directions including down the axon.
Contains large amounts of VG-Na+ channels

Front 8

Resting Potential

Back 8

Uneven distribution of cations across the membrane mediated by the Na/K-pump (~ -70mv) creating a polarized membrane (negative inside) when the cell is at rest.

Front 9

Na/K-pump

Back 9

A integral membrane protein-pump using 1 ATP to actively transport 3 Na+ ions out of the cell and 2 K+ ions into the cell.

Front 10

Initiation of Action Potential

Back 10

Influx of Na+ ions that raises the electrical potential above the "critical threshold" in an all-or-nothing event.

Front 11

Action potential is defined by

Back 11

Depolarization: Period when VG-Na+ channels open to allow influx of Na+ ions to depolarize the cell to peak voltage.

Repolarization: Outflow of K+ ions through slow-acting VG-K+ channels. Occurs a little before peak voltage.

Front 12

Hyperpolarization

Back 12

Period after repolarization that allows the outflow of many K+ ions to cause the membrane potential to drop below resting potential.

Front 13

Absolute Refractory Period

Back 13

Period when no stimulus can initiate another action potential. Begins when VG-Na+ channels inactivate at peak voltage and continues as the cell is repolarizing.
Na+ and K+ ions are on opposite sides!!!

Front 14

Relative Refractory Period

Back 14

Period when cell is susceptible to another action potential but requires an abnormally large stimulus.

Front 15

Accommodation

Back 15

An action potential that may not occur due to a threshold stimulus happening too slowly.

Front 16

Schwann Cells

Back 16

Encase long, discrete sections of the axons of neurons in the PNS by wrapping layers of their plasma membranes around the axon, creating myelin sheaths.

Front 17

Oligodendrocytes

Back 17

Wraps layers around the axon, creating myelin sheaths in the CNS.

Front 18

Nodes of Ranvier

Back 18

Small, unmyelinated areas of the axon that occur in regular intervals down the axon's length and permit saltatory conduction.

Front 19

What is the significance Myelin Sheaths and Saltatory Conduction?

Back 19

Myelin insulation significantly accelerates the transmission of impulse as depolarization jumps from one node of Ranvier to the next, effectively skipping across long, insulated portions of the axon.

Front 20

Nervous tissue support cells

Back 20

Glial or Neuroglia Cells: Outnumber neurons 10 to 1. Capable of dividing (eg. brain injury)

Front 21

6 types of Glial cells and function

Back 21

1) Microglia
2) Ependymal Cells
3) Satellite Cells
4) Astrocytes
5) Schwann Cells
6) Oligodendrocytes

Front 22

Microglia

Back 22

Arise from monocytes (WBCs) and phagocytize microbes and cellular debris in CNS.

Front 23

Ependymal Cells

Back 23

Epithelial cells that line space containing cerebrospinal fluid and use cilia to circulate the cerebrospinal fluid.

Front 24

Satellite Cells

Back 24

Support ganglia (PNS).

Front 25

Ganglia

Back 25

Groups of cell bodies in the PNS.

Front 26

Astrocytes

Back 26

Star-shaped neuroglia in the CNS that give physical support to neurons, and help maintain mineral and nutrient balance in the interstitial space.

Front 27

White Matter

Back 27

The appearance of myelinated axons.

Front 28

Gray Matter

Back 28

The appearance of neuronal cell bodies (soma).
Cerebrum has a gray appearance.

Front 29

VG-Ca2+ Channels

Back 29

Open when action potential impulse reaches the synapse allowing the influx of Ca2+ ions that bind to regulatory proteins and causes exocytosis of NT vesicles.

Front 30

Structure of Synapse (3):

Back 30

1) Presynaptic Neuron- contains and releases neurotransmitters through the presynaptic membrane.

2) Synaptic Cleft- space between the presynaptic membrane and the postsynaptic membrane.

3) Postsynaptic Membrane- contain ligand-gated ion channels; located on neurons, muscles, glands, or organs.

Front 31

Chemical Synapse or (Motor-Plate end; neuron to muscle)

Back 31

Terminal end of the axon containing neurotransmitters just inside the presynaptic membrane; unidirectional.

Front 32

Electrical Synapse

Back 32

Uncommon and bidirectional synapse. Composed of gap junctions between cells that signals much faster than chemical synapses. (eg. cardiac muscle, visceral smooth muscle, escape reflexes, retina of vertebrates)

Front 33

Ligand-gated ion channels

Back 33

Postsynaptic receptors which bind specific neurotransmitters serving as ligands that induce an open conformational change to allow the influx of ions.

Front 34

What happens to neurotransmitters after they bind and quickly release from post-synaptic membrane? (3)

Back 34

1) Slowly diffuse out of synaptic cleft
2) Degraded by enzymes
3) Relocate back to presynaptic neuron via active transport

Front 35

Acetylcholine esterase

Back 35

Enzyme that degrades acetylcholine in synaptic cleft to keep neurons from actively firing.

Front 36

MAO and COMT
(Monoamine Oxidase and
cate-chol-O-methy transferase)

Back 36

Metabolites that render epinephrine inactive by oxidizing and methylating, respectively. (2)

Front 37

Exponential decline

Back 37

The declination of stimulus with distance from synapse after EPSP or IPSP

Front 38

EPSP

(Excitatory Postsynaptic Potential)

Back 38

Combination of firing synapses creating a excitatory change where Na+ gates open to become depolarized ----> action potential continues (~40-80 synapses)

Front 39

IPSP

(Inhibitory Postsynaptic Potential)

Back 39

K+ gates open (out) and further polarizes postsynaptic neuron---> difficult to generate action potential

Front 40

G-Protein

Back 40

Common receptor protein along the inside of a post-synaptic membrane that initiates a second-messenger system.

Front 41

The _____-subunit of the G-protein breaks free upon receptor-binding and activates....(4)

Back 41

-alpha-subunit
1) activates separate specific ion channels
2) activates a second messenger (i.e. cAMP, cGMP)
3) activates intracellular enzymes
4) activates gene txn

Front 42

Acetylcholine

Back 42

Neurotransmitter:
excitatory response @ neuromuscular junctions
inhibitory response @ other junctions (vagus nerve)

Front 43

GABA

Back 43

Inhibitory NT among neurons in the brain

Front 44

Somatic Nervous System

Back 44

-Controls voluntary actions.
-Stimulus from external environment and innervates skeletal muscle; uses ACh on nicotinic receptors.
-1 sensory neuron (synapse in CNS) and 1 motor neuron

Front 45

ANS (Autonomic Nervous System)

Back 45

-Controls involuntary action.
-Receives signals from visceral organs and innervates smooth/cardiac muscle, and glands.
-Divided into Sympathetic and Parasympathetic Nervous Systems.

Front 46

How many motor neurons does the ANS use?

Back 46

2!
1) Presynaptic neuron= CNS, uses ACh
2) Postsynaptic ganglion= PNS, uses ACh or adrenaline

Front 47

Sympathetic Nervous System

Back 47

"Flight or Flight"
-Cell bodies lie far from effectors.
-Signals come from spinal cord (ventral area).
-Use adrenic receptors on effectors

Front 48

Parasympathetic Nervous System

Back 48

"Rest and Digest"
-Cell bodies lie inside or close to effectors.
-Signals come from lower spinal cord and brain ('para')
-Use nicotinic receptors (ganglion) and muscarinic receptors (effectors)

Front 49

What and where are muscarinic receptors found?

Back 49

-Type of cholinergic receptor (nicotinic is other)
-Found on effectors of parasympathetic nervous system

Front 50

CNS (Central Nervous System)

Back 50

-Brain and spinal cord.
-Composed of interneurons

Front 51

PNS (Peripheral Nervous System)

Back 51

-Conveys information to and from nervous system.
-Divided into ANS and somatic nervous system

Front 52

What are the 5 types of stimuli humans respond to?

Back 52

1) tactile=touch
2) olfactory=smell
3) gustatory=taste
4) auditory
5) visual

Front 53

What is the function of sensory receptors?

Back 53

Register a given stimulus and gather information

Front 54

What are the 5 main sensory receptors?

Back 54

1) MECHANO= stretch, tactile, proprioceptors, auditory
2) CHEMO= olfactory, gustatory
3) THERMO
4) ELECTROMAGNETIC= photoreceptors
5) NOCIECEPTORS= pain

Front 55

Sensory Neurons

Back 55

Afferent Neurons.
-Carry information from sensory receptors to CNS.

Front 56

Interneurons

Back 56

Associative Neurons.
-Relay and process info between neurons in CNS

Front 57

Motor Neuron

Back 57

Efferent neuron or effector.
-Convey signals from CNS to target (muscle, gland, or organ)

Front 58

What does the neural tube give rise to?

Back 58

-Brain (anterior)
-Spinal Cord (posterior)

Front 59

What 3 components protect the CNS?

Back 59

1) Meninges; connective tissue
2) Bone; spinal cord and skull
3) Cerebrospinal Fluid (CSF); liquid shock absorber

Front 60

What does the hindbrain become?

Back 60

-Cerebellum
-The Pons
-Medulla Obligata

Front 61

What is the function of the midbrain?

Back 61

-Integration of visual and audio info

Front 62

What 2 dinosaurs arise from the forebrain?

Back 62

-diencephalon
-telecephalon

Front 63

What 3 structures is the diencephalon composed of?

Back 63

-Hypothalamus
-Thalamus
-Pituitary Gland

Front 64

What 3 structures is the telecephalon composed of?

Back 64

-Basal Nuclei
-Limbic System
-Cerebral Cortex or Cerebrum

Front 65

Cerebral Cortex or Cerbrum splits into these lobes...

Back 65

Frontal
Parietal
Occipital
Temporal

Front 66

Function of Spinal Cord

Back 66

-simple spinal reflexes
-control of primitive processes i.e. walking, urination, function of sex organs

Front 67

Medulla: location and function?

Back 67

-Hindbrain
-Controls autonomic processes (i.e. blood pressure, heart rate, respiratory rate, reflexes like sneezing+vomiting)

Front 68

The Pons: location and function?

Back 68

-Some autonomic processes
-anti-gravity and posture balance

Front 69

Cerebellum: location and function?

Back 69

-Integration center
-Coordination of refined and complex movement, balance, and posture (i.e. dancing, sewing, piano)

Front 70

Thalamus: location and function?

Back 70

-Forebrain diencephalon
-Somatic conscious sensation

Front 71

Hypothalamus: location and function?

Back 71

-Forebrain diencephalon
-Homeostasis (i.e. body temperature)
-Primitive emotions (i.e. appetite, rage, sex drive)

Front 72

Pituitary gland: location, regulation, and function?

Back 72

-Forebrain diencephalon
-Regulated by the hypothalamus
-Homeostasis via hormone release
-Anterior Pituitary releases 6 peptide hormones
-Posterior Pituitary releases 2 peptide hormones

Front 73

Basal Nuclei: location and function?

Back 73

-Forebrain telecephalon
-regulate body movement

Front 74

Limbic System: location and function?

Back 74

-Forebrain telecephalon
-emotion

Front 75

Cerebral Cortex or Cerebrum: location and function?

Back 75

-Forebrain telecephalon
-Higher thought processes: cognition, attention, memories, intelligence, language/communication, abstract thought, reading

Front 76

What does the corpus callosum do?

Back 76

Thick bundle of axons connecting the right and left hemispheres of cerebrum.

Front 77

Simple Reflex Arc

Back 77

-Rapid, monosynaptic reflex involving 1 sensory and 1 motor neuron
-Belongs to PNS

Front 78

Function of Vestibular and Auditory Systems

Back 78

1) maintenance of postural equilibrium and balance
2) reception of sound

Front 79

What are the 3 parts of the ear?

Back 79

-outer ear
-middle ear
-inner ear

Front 80

Outer Ear

Back 80

-pinna (ear flap)
-auditory canal

Front 81

Middle Ear

Back 81

-tympanic membrane or eardrum
-malleus, incus, stapes

Front 82

Inner Ear

Back 82

-Oval window (small entry)
-Cochlea
-Hair cells in Organ of Corti
-Vestibular apparatus: Semicircular canals

Front 83

Movement of Sound through Ear

Back 83

1. Sound enters pinna and is directed through ear canal (outer ear)
2. Produces vibrations at tympanic membrane which travel through malleus, incus, and stapes which act as a lever system, ↑F (middle ear)
3. -Goes through small oval window (↑P), spirals in cochlea and causes movement of hair cells (cilia) at the Organ of Corti that tranduces into neuronal signals.

Front 84

Travel of Light through Eye

Back 84

1. Light refracts of cornea -->transverses through aqueous humor
2. Passes through pupil and lens
3. Proceeds through vitreous humor until it reaches photoreceptors at the retina

Front 85

Cornea

Back 85

Transparent layer which refracts light at front of eye through the aqueous humor

Front 86

What are the 2 liquid-gel cavities of the eye?

Back 86

-the aqueous humor (anterior)
-vitreous humor (posterior)

Front 87

Iris

Back 87

-Colored portion of eye
-Muscular tissue that constricts and dilates to regulate amount of light through pupil

Front 88

Lens

Back 88

Converging lens that can:
-flatten (farther focal point)....eyes wide open
-contract (closer focal point)...eyes squinting

Front 89

Ciliary Body

Back 89

Circular muscular tissue surrounding the lens that controls focal length by contracting and relaxing

Front 90

Retina

Back 90

Back portion of eye containing photoreceptors (rods and cones)

Front 91

Rods

Back 91

-Registers black/white and dim light
Dark: Depolarized---->inactive rhodopsin
Dim Light: Hyperpolarized-----> active rhodopsin

Front 92

Cones

Back 92

Register bright light and colors
-uses the protein opsin (similar to rhodopsin)

Front 93

What is the largest organ in the human body?

Back 93

Skin

Front 94

3 main functions of the skin?

Back 94

1. Maintain body temperature
2. Environment sensory input
3. Protection barrier

Front 95

Other 4 functions of the skin?

Back 95

4. Excretion
5. Immunity
6. Blood reservoir
7. Vitamin D synthesis

Front 96

3 main layers of the skin?

Back 96

-epidermis
-dermis
-subcutaneous layer

Front 97

Epidermis

Back 97

Avascular, stratified squamous epithelium that consists of 5 separate layers

Front 98

Stratum Corneum

Back 98

-Most outer layer of epidermis
-Many layers of dead cells and keratin protein
-Forms waterproof-like barrier

Front 99

Stratum Germinativum

Back 99

-inner epidermis layer
-skin cells differentiate
-where keratin is produced (loses nuclei)

Front 100

Dermis

Back 100

-Thickest layer of skin below epidermis
-Derived from mesodermal tissue

Front 101

Where would you find blood vessels, nerves, sebaceous (oil) and sweat glands???

Back 101

Dermis

Front 102

Subcutaneous Layer

Back 102

-Most bottom layer of skin
-Composed of adipose tissue--->insulation & protection