Uke 7 B-N kap 2: makroanatomi

What are the two most important celltypes in the neurosystem?

neurons
gliacells

Name three neuron types

Motor neurons
Sensory neurons
Interneurons

What is the neuron's 4 divisions, their main part, and their function?

1. input-zone: dendrites
The celular extension of a neuron receives infomation via the synapse of the other neuron.

2. Integration zone: neurons cellbody (soma)
Neurons cellebody integrates informastion that the neuron received from the dendrite, and decides if a signal will be sent away.

3. Conduction zone: axon
A singular extension, the axon, leads the neurons signal away from the cellbody

4. Output zone: axon terminals
Specialized swellings at the ends of the axon transfers the signal across the synaps to another cell.

How can neurons be classified, and what are the form categories?

By function, size and form

The form categories:
o Multipolar neurons:
many dendrittes and a single axon
o Bipolar neurons:
A single dendritte in one and and a single axon in the other end
o Unipolar neurons:
A single extension, usually a axon, which parts in to directions from the cellbody. One end with input-zone and another end with the output-zone

By function

• Sensoric neurons

• Motor neurons

• Internal neurons

What are the three main components of a synapse?

o Presynaptic membrane

o Synaptic cleft

o Postsynaptic membrane

How is information tranfered from neuron to another cell/neuron (through synapses)?

Elektrisk aktivitet i axon
--> neurotransmittere slippes ut til synamptic cleft
--> neurotransmittere interagerer med macthende post-synaptiske neurotransmitter-reseptorere hvor de fanger og reagerer på neurotransmittere
--> fører til lokale endringer
--> neuron sender ut egne neurotransmittere som sendes til neste neuron

What is the function of the axon?

Axonet integrerer og utsender informasjon

I axon hillock blir informasjon fra synapsene på dendrittene og cellekroppen samlet og integrert

How does the axon and axon terminals receive substances needed for their functions?

Receives them through the neurons "Golgi appartus", through axon transport:

o Transport-vesicles: spheres with specialized motor-proteins
o Proteins transport vesticles along the microtubiules at the inside of the axon + between the cellebody and axon terminals
Two forms of transport?
o Anterogade transport
o Retrograde transport

What are the 4 types of glia cells, which exist in the brain and what are their functions?

o Astocytes (exist in the brain)
Receives synapses directly from neurons. Surrounds and monitor activity of close-lying neuro synapses.
Creates new synapses.

Most common type

o Microglial cell (exist in the brain)
Extends and removes tiny processes, ex. dangerous substances.
Cleanup crew

o Oligodendrocytes (exist in the brain)
Does the function of myellnation: wraps sections of an axon in myelin for the brain and spinal cord.
Gives signals that betters the structural integraty of axons.

o Schwann cells: (do not exist in the Brain)
Utøver myelination i resten av kroppen)

What are the two subdivisions of the nervous system?

Peripheral nervous system
Central nervous system (CNS)

What are the two subdivisions of the Peripheral nervous system?

Somatic nervous system
Autonomic nervous system

WHat is the general function of the somatic nervous system, and what does it consist of?

Through this system, the brain can controll movement and receive sensoric information from the body.

Consists of:
Cranial nerves (12 pair)
Spinal nerves (31 par)

WHat is the general function of the autonomic nervous system, and what does three groups does it consist of + their main function?

Nerves that primarily control the viscera. Controll the organs in the body.

The three groups and their main function:
o Sympathetic nervous system:
gets the body ready for action
o Parasympathic nervous system:
Helps the body calm down, and prepare for future action

o Enteric nervous system
Regulates the function of the belly, under controll of the CNS

How does the autonomic nervous system span the central nervous system and the peripheral nervous system?

It does this through..
the autonomic ganglia: group of neurons located outside the CNS
the preganglionic neurons: run from the CNS to the autonomic ganglia
the postganglonic neurons: run from the autonomic ganglia to targets in the body

What are the visible brain-properties of the central nervous system? + some functions of them

o Two cerebral hemispheres

o Cerebral cortex (gray matter): thick tissue layer outside the brain. Receives and prosesses information + involved in complex cognition.

o Under this: white matter
Consists mostly of axoner. Sends out information to other locations.

What is the cerebral cortex?

it is the folded outermost layer of the cerebral hemispheres.

The folds (gyri and sulci) increases the amount of cortex that can fit into the skull and are grouped together into lobes

what are the four important lobes/cortal regions + what function + how do they communicate?

o Four important cortical regions
Frontal lobe (high level cognition, motor control)
Parietal lobe (sensory information)
Temporal lobe (auditory information)
Occipital lobe (Visionary information)

o The four cortical regions communicate together through axonal tracts

how are the neurons in the cerebral cortex organised?

The neurons in the cerebral cortex are organized into 6 layers

There are some structures that only consist of 3 layers or that are not organized

What processes are the subcortial structures involved in?

Movement and emotion-regulation

Name two subcortial structures

• Basal ganglia:
  Exist in the cerebral cortex and midbrain

• Limbic system:
  Kritisk for emosjoner og læring
  Består blant annet av amygdala og hippocampus

The diencephalon is a part of the forebrain. What is its functions, and what are the thwo main components?

Diencephalon leads sensoric information and controlls basic physiological functions.

- Thalamus:
Leder nesten all innkommende sensorisk informasjon til riktig region
- Hypothalamus:
Involvert i mange vitale funksjoner som, sult, tørste, sex osv.

What is the top of the midbrain called, and what is the majority of the midbrain called? WHat are these parts main function?

Top: tectum: process visual and auditory information

Majority: tegmentum. Has many important motor centers

What are two important motor centers in the midbrain, , and what do they do?

Substantia nigra: neurons that release dopamine

Red nucleus: communicate with motor neurons in the spinal cord

What is the cerrebellum, pons and medulla's functions?

cerrebellum: motorisk koordinering og kontroll

pons: viktig for motorikk + sensorisk informasjon

medulla: vedlikeholder vital grunnleggende kroppslige funksjoner

What are the three protective membrane layers in the brain called together, and that are the three layers called?

meninges (samlet betegnelse)
Ytter lag: dura mater
Mellomlag: arachnoid
Underlag: pia mater

What is arachnoid, what fluid does it create, and why is it important?

Is a substance that creates a resere, subarchnoid space, which leads to the brain bathing in cerebrospinal fluid (CSF) (ryggmargsvæske)

Two important functions of CSF:
o 1. shock-absorber for hjernen à beskyttende funksjon
o 2: er et medium for utvekslingen av materialer, som næringsstoffer, mellom blood vessels og hjernevev

How does cerebrospinal fluid circulate in the brain?

venticular system

Hver hjernehalvde består av en lateral ventricle + third og forth ventricle. Disse er hulrom som er fylt med CSF
o Disse produserer CSF ved å filtre blod

Which system removes waste substances etc. from the brain?

Glymphatic system

What are the most important arteries for the brain?

. Hoved årene i hjernen er carotid arteries, som gir blod til anterior og middel cerebral arteries, som videre gir blod til cerebral hemispheres.

utvikling av hjernedeler (se bilde)

XXXX

retninger å se hjernen fra + planer