Bio 30 UNIT A - Chapter 13 - Neurons

neurons

neurons

special cells that conduct electrochemical implulses over long distances

glial cells

• glial comes from ‘glue’

• they support neurons

• helps neurons close without letting them touch

where are glial cells important?

they support neurons and help neurons close without letting them touch

examples of glial cells

• astrocytes: clean up brain debris and transports nutrients

• Schawann cell: form the myelin

cell body / soma of a neuron (4)

• contains special cytoplasm called neuroplasm

• shape/location of cell body varies based on type of neuron

• contains nucleus

• widest part of the neuron

dendrites (3)

• short extensions from the cell body which contain receptors for neurotransmitters (no bumps)

• they pick up electrical impulses and direct them down the neuron

• diff patterns based on the location and what they recieve

axon

• extension in neuroplasm from the cell body (long up to 1m in length, and skinny)

• carries impulses picked up in dendrites to another neuron or effector

• axons can branch out and make new connections

• can be covered w/ schwann cells (myelin sheath)

schwann cells

• protects axon

• sends messages fast

axon terminals / synaptic terminals (3)

• bumps at the end of axon

• contain little sacs called synaptic vesicles

• little sacs ^ that look like cookies, they contain neurotranmitter that will activate their neighbouring dendrite

myelin sheath (5)

• increases speed which neural implulse can travel

• made up of schwann cells, a type of glial cell

• contains fatty protiens (looks white)

• wraps around axons like a cinnamon bun and provides axon w/ nutriens and protects it

• outlayer called neurilemma

what are myelin sheath made up of?

schwann cells, a type of glial cell

neurilemma

• outlayer of myelin sheath that contains nucleus

• partially regenerates damaged neurons

what neurons don’t have schwann cells?

• any ‘grey’ matter

• any neurons to do with thinking

node of Ranvier (4)

• space between schwann cells where the axon is unprotected (the gaps)

• impulses jump from one node to another

• the more myelin a neuron has, the faster an impulse can travel

• saltatory conduction (cos sodium is involved)

saltatory conduction (node of ranvier) (2)

• impulse jumps form one node to another

• more myelin a neuron has, the faster an impulse can travel

white matter

nerves throughout the body/brain that DO contain myelin

grey matter

• the part of the brain responsible for mental function

• this part does NOT contain myelin and cannot be fixed when destroyed

motor neurons (5)

• implulse travels from the central nervous system towards the effectors (body)

• cell body is located opposite of axon terminatls

• dendrites located @ the bottom of the cell body

• long axon

• covered in myelin cells = white matter

interneurons (6)

• impulses carried in the CNS

• interprets sensory information and sends out motor information

• cell body located at the top of the axon terminals

• dendrites are attached to the CB

• short axon

• no myelin = grey matter

sensory neurons

• impulses travel to the CNS

  • relays info from environment to CNS for processing

• cell body is attached on axons

• dendrites in the skin

  • dendrites have modified sensory receptors on their ends to receive external stimuli

• long axon

• covered in myelin = white matter

if a substance looks white then: (myelin sheath)

it contains fatty proteins

what can partially regenerate damaged neurons?

neurilemma