Unit 4: Nervous System Vocab

integral and Peripheral

Types of Membrane Proteins

Integral Proteins

proteins embedded in the center of the membrane, hydrophobic sides contact fatty acid tails

Peripheral Proteins

proteins temporarily attached to integral proteins, hydrophilic

Facilitated Diffusion

movement of large or polar molecules via membrane proteins; allows only SPECIFIC solutes to cross, without using ATP

Channel Proteins

integral proteins through which molecules can move in either direction, from high to low concentrations, without ATP

Voltage-gated Ion Channels

proteins that open & close in response to change in charge across the membrane

Nicotinic Acetylcholine Receptors

specific neurotransmitter binding causes conformation to change, opens pore, allowing Na+ to diffuse into postsynatptic neuron

Active Transport

process that moves solutes against their [] gradient, in one direction, by using ATP

Pump Proteins

proteins that bind to specific solutes to cause conformational change and move them against their gradient

Cotransport

coupling of a "downhill" diffusion of one solute with an "uphill" transport of another against its concentration gradient

Secondary Active Transport

type of transport that does not directly use ATP; rather utilizes a previous gradient initially set through the usage of ATP

Bulk Transport

type of transport that allows larger solutes to enter/exit the cell by breaking the phospholipid bilayer and forming vesicles

Endocytosis

vesicles fuse with plasma membrane transferring contents from outside of the cell inside

Phagocytosis

type of transport, where solid substances from outside the cell are sent to lysosomes

Pinocytosis

type of transport, where liquids & dissolved solutes enter the cell from the outside

Exocytosis

vesicles fuse with plasma membrane expelling contents from inside of the cell outside

Central Nervous System

consists of brain and spinal cord

Peripheral Nervous System

connects CNS with rest of body

Neurons

nerve cells that relay messages via electrical impulses

Neuron Structure

Consists of Soma, Dendrite, Axon, and Axon Terminals

Soma

cell body of neuron containing nucleus, organelles, and cytoplasm, carries out metabolic functions

Dendrite

multiple, short fibers that receive and convert chemical information from other neurons to electrical impulses

Axon

single, elongated fiber that passes electrical impulses to synapses to relay information to other neurons or effectors

Myelin Sheath

layer of fatty tissue that wraps around the axon of many neurons; increases transmission speed of neural impulses

Oligodendrocytes

supporting cells of the central nervous system responsible for the formation of myelin.

Schwann Cells

supporting cells of the peripheral nervous system responsible for the formation of myelin.

Nodes of Ranvier

gaps in the myelin sheath to which voltage-gated sodium channels are confined

Synapse

junction between two neurons and/or other neurons and effector cells (narrow, about 20 nm)

Neurotransmitters

chemical messengers that cross the synaptic gaps between neurons because synapses lack membranes

Oscilloscopes

device that measures membrane potential, consists of two electrodes placed inside and outside of neuron

Membrane Potential

voltage difference across a cell's plasma membrane due to imbalance of ions

Resting Potential

charge across the membrane when the neuron is NOT firing; -70mV (more negative inside than outside)

Action Potential

change in membrane potential which produces a neural impulse; a brief electrical charge that travels down an axon; "firing"

Depolarization

membrane potential becomes more positive, going from -55 mV to +30 mV, as Na+ rushes into the axon

Repolarization

membrane potential becomes more negative as K+ rushes out of the axon

Hyperpolarization

exiting K+ surpasses resting potential and membrane potential becomes more negative

Refractory Period

state of recovery where neuron cannot fire again, prevents action potential from traveling backward

Threshold Potential

stimulus must be strong enough to surpass -55mV to initiate an action potential; any signal less than this will not

All-or-None Principle

refers to the idea that the action potentials always occur at the same magnitude, independent of stimulus, or not at all

AP Propagation

movement of an action potential along an axon; depolarization creates concentration gradient between adjacent areas of axon, leading to diffusion occurring across these regions

Saltatory Conduction

conduction of action potentials along myelinated axons from one node of Ranvier to the next, increasing the speed of action potentials

Calcium Channels

voltage-gated proteins that allow neurotransmitters to undergo exocytosis with the axon terminal

Reuptake

presynaptic neuron's absorption of the excess neurotransmitters

Excitatory Postsynaptic Potentials (EPSP)

type of signal that depolarizes postsynaptic neurons by opening Na+ or Ca2+ channels (full name)

Acetylcholine

neurotransmitter that initiates muscle contractions; made from substances from diet and aerobic respiration

Neuromuscular Junctions

synapse where a motor neuron comes into contact with a skeletal muscle cell

Acetylcholinesterase

enzyme that breaks down acetylcholine

Exogenous Chemicals

chemicals that enter body from outside sources

Neonicotinoids

synthetic chemicals found in insecticides that bind to complementary receptors but cannot be degraded by enzyme

Cocaine

excitatory psychoactive drug that binds to and blocks dopamine reuptake transporters, resulting in dopamine build-up

Inhibitory Postsynaptic Potentials (IPSP)

type of signal that hyperpolarizes postsynaptic neurons by opening Cl- channels (full name)

GABA

major inhibitory neurotransmitter that calms the nervous system to process sensory input in an organized way

Summation

process in which all neurotransmitters combine to fire an action potential; threshold is reached if depolarization is greater than hyperpolarization

Consciousness

awareness of ourselves and environment

Emergent Properties

idea that the system is greater as a whole rather than any one component or the sum of its parts

Motile or Sessile

types of locomotion

Muscle Fibres

together makes up a muscular bundle wrapped in connective tissue

Myofibrils

together makes up muscle fibres & is responsible for contractions

Sarcomeres

repeating units that make up myofibrils

Myosin

thick filament with protruding heads that make up the sarcomere

Actin

thin filaments that make up the sarcomere

Motor Unit

consists of one motor neuron + neuromuscular junction + hundreds of muscle fibres

Sarcolemma

plasma membrane of a muscle cell

T-tubules

infoldings of the sarcolemma which exist through the cell and help spread action potentials

Sarcoplasmic Reticulum

specialized endoplasmic reticulum of muscle cells that store calcium

Z-lines

made of protein discs, marks end of sarcomeres and anchors actin

Striation

alignment of actin and myosin filaments which show muscles to have a striped pattern

A band

dark area of the sarcomere where myosin and actin overlap

H zone

lighter area of the sarcomere where only myosin is present

I band

lightest area of the sarcomere where only actin is present

Troponin

regulatory protein that controls muscle contractions by binding to calcium ions

Tropomyosin

regulatory protein that controls muscle contractions by covering myosin binding sites on actin

Cross-bridge

connection of a myosin head to actin filament during muscle contraction

ATPase

enzyme that catalyzes hydrolysis of ATP which allows the tilting of myosin heads

Antagonistic Muscles

pair of muscles that coordinate opposite movements by allowing one to contract while other relaxes (ex bicep and tricep)

Intercostal Muscles

pair of muscles that allow ribs to move in opposite directions during breathing

Titin

largest polypeptide in humans that binds to myosin and acts as a molecular spring, storing potential energy

Elastic Recoil

tendency of muscles to return to the resting state after contraction

Exoskeleton

external system, found in arthropods, crustaceans, and insects; made of chitin

Endoskeleton

internal system, found in vertebrates, made of bone

Point of insertion

site where muscle is attached to a moving bone

Cartilage

smooth tissue that lines bone, absorbs shock, reduces friction and prevents bone on bone contact

Synovial Fluid

Provides O2 and nutrition for cartilage, lubricates joint to reduce friction

Ligaments

attach bone to bone, prevent abnormal movements, tough tissue with large amounts of collagen

Joint Capsule

seals joint and prevents dislocation

Tendons

attach bone to muscle, tough tissue with large amounts of collagen

Articulated Joints

Joints that allow movement

Sutures

fixed joint that does not allow movement (bones of skull)

Hinge

joint that allows moves along a single axis like knee, can flex (bend) and extend (straighten)

Ball-and-Socket

joint that has a greater range of motion like the hip joint, can protract/retract, abduct/adduct, and rotate

White Matter

type of tissue in the spinal cord made of myelinated axons

Grey Matter

type of tissue in the spinal cord made of unmyelinated axons; like interneurons

Unconscious

processes that occur without awareness like reflexes or other involuntary actions

Receptors

specializes structures that allow living organisms to detect the conditions of their internal or external environment.

Sensory Neurons

relay messages to the CNS by firing action potentials

Interneurons

neurons within the brain and spinal cord that communicate internally and intervene between the sensory inputs and motor outputs

Motor Neurons

carry outgoing information from the brain and spinal cord to muscles and glands

Effectors

final destination that carries out a response, usually muscles or glands

Motor Cortex

area in the frontal lobes that controls voluntary movements

Cerebral Cortex

neural cells covering the brain; the body's ultimate control and information-processing center