Human Nervous System and Sensory Organs Flashcards

Flashcards for reviewing the human nervous system and sensory organs.

Stimulus

Light, sound, touch, pressure, taste, temperature and chemicals. An organism must be able to respond to its environment.

Nervous System

A coordination system in complex animals and humans responsible for rapid reactions.

Endocrine System

A coordination system in complex animals and humans using hormones for slower reactions.

Central Nervous System (CNS)

The main division of the human nervous system, consisting of the brain and spinal cord.

Peripheral Nervous System (PNS)

A division of the human nervous system comprised of 12 pairs of cranial nerves and 31 pairs of spinal nerves.

Receptors

Structures that perceive a stimulus and send the impulse to the CNS.

Effectors

Nerves or glands that receive processed information from the CNS.

Neurons

The structural units of the nervous system responsible for conducting nerve impulses.

Neuroglia

Connective tissue between neurons that bind and nourish neurons.

Myelin Sheath

Structure enclosing nerve fibers, formed by Schwann cells, that isolate the nerve fibers and accelerates conduction.

Synapse (Synaptic Cleft)

Gap between the axon of one neuron and the dendrite of the next, where nerve impulses are transmitted.

Acetylcholine or Serotonin

Neurotransmitters that fill Synaptic vesicles.

Synapse Significance

Impulse only moves in one direction, can be transferred to more than one neuron & Synapse determines which stimuli are transmitted

Serebrospinale Vloeistof Functions

Shock absorption, Supplies neurons nutrition and steering neurons, Removes waste & Maintain constant pressure in CNS

Grey matter

Darker cell bodies and dendrites of neurons.

White matter

Myelinated axons (due to fatty sheathes).

Cerebrum

Largest part of the brain responsible for voluntary actions, sensations and higher mental functions.

Cerebral Cortex

Outer layer of the cerebrum with folds and grooves that enlarge the brain surface area.

Corpus Callosum

C-shaped structure between the two cerebral hemispheres, composed of white matter axons that Forms a bridge for communication.

Cerebellum

Structure behind and below the cerebrum that coordinates and controls all voluntary actions and controls the muscle tone.

Medulla Oblongata

Extension of the spinal cord that conducts nerve impulses between the spinal cord and the brain; Control the autonomic functions.

Spinal cord

Provides a pathway, ascending tracts. descending tracts & Contains reflex centers

Dorsal root

sensory neurons Possess a swollen part the GANGLION (Cell body)

Ventral root

motor neurons

Mixed Spinal Nerve

Dorsal and ventral roots meet to form the

Reflex

Rapid, involuntary response of an effector to a stimulus

Sympathetic division

Prepares body for emergency Fight-or-flight response

Parasympathetic division

Allow body to return to normal

Alzheimers se siekte (AS)

Onomkeerbare, stadig verergerende breinsiekte, Plaakaanpaksels tussen neurone & Neurotransmitter deficiency

Multiple sclerosis (MS)

Outo-immuuntoestand Immune system systematically destroys myelin sheaths

Spinale skade

Trauma. Motorongeluk, Geweld Falling / Paralysis, Paraplegia or quadriplegia

Breinskade

Kanker Infeksie / Loss of consciousness, Concussion, Headaches, Dizziness and confusion

Dwelmmiddels

Stimuleer of inhibeer NEURO- OORDRAGSTOWWE / Any remedy that alters normal body function Physically or psychologically

Most common neuro- transmitters

Endorfien, Serotonien, Dopamien

3 hooftipes dwelmiddels

Stimulante, Depressante, Hallusinogene

Lae tot medium dosisse Dagga

Lomerigheid, Verminderde koördinasie Gevoel van genot, veranderde sin vir tyd en ruimte

Heroïen

Bootst endorfiene na en blokkeer hul reseptore/ Onderdrukte pyn, Neerdrukkende effek op die sentrale senuweestelsel

Ecstasy

Oormatige vrystelling van neuro-oordragstof, serotonien, oorstimuleer die brein Blokkeer die heropname van serotonien in die sinapse

TIK

versnelde asemhaling Wakker / Kragtige sintetiese dwelm wat senuweeselle stimuleer

Oog

Fotoreseptore ontvang stimuli Ligstimuli

Sclera

Sterk, wit, onelastiese bindweefsellaag Funksie: Beskerm inwendige dele/Outer fibrous layer

Kornea

Voorste deursigtige deel van die sklera Meer konveks. Laat lig deur Breking van inkomende strale/ Outer fibrous layer

Choroïed

Dun donker gepigmenteerde, bloedvatryke laag Dun donker gepigmenteerde, bloedvatryke laag voedingstowwe/ Middle vascular layer

Siliaarliggaam

Bestaat uit siliaarspiere en suspensoriese ligamente Funksie: Oogakkommodasie/ Middle vascular layer

Lens

Rubberagtige elasitiese, deursynende bikonvekse struktuur Funksie: Verander vorm sodat duidelike beeld vorm/ Middle vascular layer

Geelvlek

Reg in die middel = FOVEA CENTRALIS Only cones

Oogsenuwee

Funksie: Gelei senuwee-impuls na die serebrale korteks Plek waar senuwee die oog verlaat – BLINDEVLEK Geen beeld word daar gevorm/ Inner light sensitive

Uitwendige oor

Oorskulp (pinna) Kraakbeen met vel bedek Funksie: Vang klankgolwe op en rig dit na die gehooropening

Middeloor

Drukgolwe in die perilimf word geabsorbeer Opening net onder die ovaalvenster

Inwendige oor

Besit `n reseptor = MAKULA Gevul met endolimf binne die perilimf

Makula

In die utrikulus en sakkulus Verskaf inligting ivm die POSISIE VAN DIE KOP IN DIE RUIMTE

Cristas

Neem VERANDERING IN SPOED OF BEWEGING VAN DIE KOP WAAR/ In die Ampulla van die halfsirkelvormige kanale

Gehoorgebreke

Oorerwing, Ouderdom & Opbou van was voor die timpanummebraan

Visuele gebreke

Katerakte Verdowwing van die lens of Verdowwing van die lens