Central and peripheral nervous system

Question 1

What is the definition of a neuron

Answer 1

Neurons are nerve cells the functional unit of the nervous system designed for communication and they are highly specialised

Question 2

What is the cell body (Soma)

Answer 2

The part of the neuron containing the nucleus it controls the function of the cell it is surrounded by cytoplasm containing mitochondria endoplasmic reticulum ribosomes and the Gogli aprutus

Question 3

What is the function and structure of the dendrites

Answer 3

Short extensions of cytoplasm they are highly branched and carry messages electric nerve impulses to the cell body

Question 4

What is the function of the Axon

Answer 4

A single long extension of cytoplasm which carries nerve impulses away from the cell body at the end of the axon it divides into many small branches each branch is an axon terminal the length of an axon depends on where it is located in the body

Question 5

What is the function of the Myelin sheath

Answer 5

The Myelin sheath is what covers the axon with in white fatty material it acts as an insulator and protects the axon from damage it also speeds up the movement of a nerve impulses along the Axon it is made from Schwann cells

Question 6

Explain what a synapses is (needs more information)

Answer 6

A Psynapse is the junction of axon terminals of one of the dendrites or so body the neurons do not fully meet as there is a small gap between them messages are then carried between these gaps occurring by the movement of neurotransmitters

Question 7

What is the function of the Neurilemma

Answer 7

Coats the Mylynn sheath to help repair injured fibres

Question 8

Node of Rainier

Answer 8

The gaps between the Mylynn sheath allowing for solidarity conduction

Question 9

What is the function of Schwann cells

Answer 9

Forms the myelin sheath

Question 10

Outline the difference between multipolar bipolar and unipolar and pseudounipolar nerves

Answer 10

Multipolar: axon: 1

dendrites: many
example: moter neuron/ interneuron

Bipolar:
axon: 1
dendrites: 1
example neuron in ear nose and eye

Unipolar:
Axon: one
dendrites: nill
example: not found in humans

pseudounipolar:

axon: one axone which divides into two
dendrites none
examplea; sensory neuron

Question 11

Explain the function of a glial cell

Answer 11

glial cell surrounds neurons and protects and supports and assist in creating environment for affective electro chemical communication by neurons they do not participate in the transmission of electrochemical impulses there are three glial cells for every neuron glial cell holds neurons together

Question 12

Outline the difference between afferent efferent and inter neurons

Answer 12

Afferent are also known as sensory neurons they carry messages from receptors in an organ eg skin to the central nervous system eg brain

effrent are also known as motor neurons they carry messages from the central nervous system to effectors which muscles or glands

Interneurons located in the central nervous system and on the link between sensory and motor neurons they also known as connecting neurons

Question 13

Explain the afferent division of the peripheral nervous system

Answer 13

The Affrent division is otherwise known as the sensory division of the nervous system it carries nerve impulses towards the central nervous system

It is split into the somatic and the vesercal sensory neurons

somatic: somatic sensory neuron send information from the skin and muscles

verceral;
sensory neurons send information from the internal organs

Question 14

Explain the efferent division of the nervous system

Answer 14

The afferent division of the nervous system carries nerve impulse from the central nervous system to end effector

splits to the somatic and autonomic division

somatic send impulse too skeletal muscle

autonomic send impulse too involantary muscles and organs this spits of into parasympathetic and sympathetic division

parasympathetic: controls the body while resting and quiet
sympathetic: controls body when active; fight or fight response

Question 15

Explain the environment of the neuron when it is polarised

Answer 15

the resting state of the neuron meaning there’s no stimulus the cell of the neuron will contain potential energy this comes from the difference in charge between the extracellular fluid and the intracellular fluid

The extracellular fluid is positive whereas the interest intra cellular fluid is negative the extracellular fluid contains mainly sodium irons but some potassium lines in the intracellular fluid there is a high concentration of negative ions because they are so large but there are also positive potassium ions the potential Energy is -70 mV while polarised the sodium potassium pump will regulate the flow of sodium and potassium through the cell membrane during polarisation.

Question 16

Outline how the sodium potassium pump works during polarisation

Answer 16

The pump moves two potassium ions into the cell for every three sodium ions that are removed therefore there is a net reduction of potassium ions inside the cell the movement is against a concentration gradient meaning this is active transport which also means this requires ATP

Question 17

outline what occurs when a neutron becomes depolarised

Answer 17

Stimulus must increase membrane potential to -55 mv (all or none) this occurs by opening the sodium voltage gates allowing for the sodium to enter the cell when. Once 55 MV is reach to all of the sodium voltage gate will open therefore sodium ions will flood into the cell there is then diffusion of sodium around the cell too ajacent areas causing depolarisation to the next part of the cell the intracellular fluid will now be positive and the extracellular fluid will become negative

Question 18

Outline what occurs when a cell becomes repolarised

Answer 18

The positive intracellular fluid will stimulate potassium voltage gates to open causing and outflux of potassium the extracellular fluid will then become positive again and the intracellular fluid will become negative again

the cell will become a hyperpolarised this occurs because the potassium voltage channels have been left open this lowers the membrane potential the sodium potassium pump being left open result in the redistribution of potassium therefore the cell will become polarised again the cell can be stimulated again when the membrane potential equals 70 mV when the cell cannot be stimulated this is known as the refractory period

Question 19

Explain continuous conduction

Answer 19

Continuous conduction occurs in un-methylated is movement to adjacent areas this movement stimulates the opening of the voltage gated channels which initiate actually potential this type of conduction moves at 2 m/s this process occurs repeating itself along the length of the neuron the info impulse is prevented from going backwards in the refractory period

Question 20

Explain Saltatory conduction

Answer 20

Occurs in mylinated fibres action potential jumps from node of ravier to the next allowing for nerve impulse to occur quickly at 140 m/s this is energy-efficient

Question 21

Outline the difference between a neuromuscular junction and a synapse

Answer 21

Neuromuscular junction is an attaches a neuron to a muscle or gland where is a synapse attaches a neuron to neuron

Question 22

Explain the transmission of nerve impulse across a Synapse step by step

Answer 22

overview: synaptic transmission begins when action potential reaches the axon terminal depolarisation initiates the sequence of events leading to action potential being transmitted

step one: the action potential causes depolarisation of the axon terminal membrane that calcium voltage gated channels open and calcium ions into the synaptic knob

step two: Co2 to find to synaptic vesicles fascicles move towards and bind to pre-synaptic membrane exocytosis of neurotransmitters into the synapse

Step three: neurotransmitters diffuse across Psynapse and find to receptor mediated proteins (sodium ligand Chanel) sodium extracellular fluid moves into dendrite therefore becomes the depolarised and the action potential is transmitted

step four: neurotransmitter is broken down by enzyme for example ACh is broken down by acetolinase there is an Endo side ptosis by axon terminals plus a response as to ACh

Question 23

name and describe the 3 structures that exist to prevent injury too the brain

Answer 23

• Cranium and Vertebrae (BONE)
  The outermost bones which house the brain and spinal cord
  Hard casing
• Meninges
  Protective membranes enclosing the brain.
• Cerebrospinal Fluid
  Fluid that circulates throughout CNS

Question 24

describe the 3 layers off the meninges

Answer 24

Pia mater: is the innermost layer. it is Tissue paper thin
Closely adheres to the brain and spinal cord Large amount of blood vessels. Blood-brain barrier. Allows only essential materials to enter brain.

Arachnoid mater: is the middle layer. filmy membrane that is joined to the pia mater by fine threads resembling a cobweb.
‘Cobweb’ creates a space. Cerebrospinal fluid flows in space.

Dura mater: Tough, fibrous membrane
Outermost part of the meninges
Adheres to the skull and spinal canal.

Question 25

explain Both the structure and main function of the cerebrospinal fluid

Answer 25

found Between Pia and Arachnoid Mata Circulates the CNS. Clear, colourless fluid Formed from the blood MAIN FUNCTION: Acts as a shock absorber when the CNS is hit Contains glucose, protein, urea and salts. Carries nutrients to CNS.

Question 26

Outline the structures and functions of the following structures off the cross-section of the spinal-cord ``` Dorsal route ganglion spinal nerve ventral root grey matter white matter motor neuron sensory neuron cell body Central canal of spinal cord dorsal root vertebra vertebral canal ```

Answer 26

Dorsal route ganglion Clusters of sensory neurons containing cell bodies for sensory nerves thatcarry info into the spinal-cord spinal nerve Carries motor or sensory and autonomic information between the brain and spinal cord and the rest of the body ventral root Contains a motor neurons that carry information from the central nervous system to the rest of the body grey matter un methylated contains neuron cell bodies and process information white matter Myla knighted axons censoring your own moves to the brain this is the outstanding part and the descending part the motor neuron moves away from the brain motor neuron Transmits impulses from the spinal-cord to skeletal and smooth muscle and directly controls movement of the body sensory neuron cell body Cell bodies of the censoring around that transport Info from receptor to the central nervous system Central canal of spinal cord Contains blood vessels and cerebrospinal spinal fluid dorsal root Axons of sensory neurons vertebra Protection against mechanical injury vertebral canal contains Fat stores blood vessels connective tissue and extra padding

Question 27

what are 4 important properties of reflexes

Answer 27

1. the stimulus is required to trigger a reflex 2 reflex is involuntary 3 the response is rapid 4 reflex response is stereotyped

Question 28

outline the difference between a protective reflex and a acquired reflex list some examples

Answer 28

protective : present at birth they are reflexes which protect you and are otherwise known as inate reflexes eg. saliva secretion, sneezing, constriction acquired: complex motor patterns which are learnt eg. maintaing balance, walking, sitting

Question 29

what is a reflex

Answer 29

Reflexes are rapid and automatic responses to a change in the environment. They are coordinated by the spinal-cord on an involuntary basis once the reflex has occurred and impulse is sent to the brain and the person becomes aware of the situation

Question 30

In detail explain the process which occurs for a reflex to occur

Answer 30

1. at the Sense receptor a change is detected which initiates nerve impulse at the sensory neuron 2. At the sensory neuron the nerve impulse is carried to the spinal-cord via the dorsal root ganglion 3. At the connecter neuron impulse is transmitted to a connecting neurons in Grey matter of the spinal-cord 4. at the Motor neuron connecting neuron transmits impulses to motor neuron which delivers it to the efector via the ventral root 5. A factor receives nerve impose and carries out appropriate response and the reflex occurs - impulse is also carried via upper sensory neuron to the brain and conscious response occurs

Question 31

What is the function of each of the cerebral lobes

Answer 31

Pariental: processing tactile sensory information pressure touch pain contains somatic sensory cortex and controls emotion frontal: reasoning motor skills cognition expressive thinking language this is the primary motor area allows for voluntary movement memory problem-solving planning and organising optical; interpreting the visual stimuli and information contains primary visual cortex receives import interprets from retinas temporal; contains primary auditory cortex interpreting sound language contains hippocampus and memory formation

Question 32

name and describe the structures involved in a reflex arc

Answer 32

A: receptor - detects stimulus. B: sensory (afferent) neuron- carries impulses to the cns C: dorsal root ganglion: cluster of sensory neurons and cell bodies D. dorsal root - carries axons of sensory nerves into CNS: E: grey matter - part of the brain and spinal cord made up of unmyelinated fires and nerve cell bodies. F: white matter - myelinated fibres. G: interneuron - joins sensory neuron to motor neuron H: synapse - gap between two neurons. I: ventral root carries axons of motor neurons away from spinal cord. motor neuron: effent carieus impulse too an effector K: neuro-muscular junction - the junction between the end of of a motor nerve and a muscle fibre.

Question 33

what is Alzimers disease

Answer 33

a progressive neurological disease that destroys memory and other mental functions

Question 34

1. What are the causes of Alzheimer's disease (the proteins which cause the disease) 2. how do there proteins usually function 3 . how do these proteins function in alzheimers disease 4. how does this effect the brain 5. outline the development over time

Answer 34

1. a. Senile Plaque being caused by the amyloid beta protein and b. neurofibrillary tangles caused by the tau protein 2. a. the amyloid beta protein is normally broken down by enzymes b. tau protein maintains the structure off the near skeleton holding the neuron together 3. a. ABP is on removed so plaque surrounds the neuron b. TP detaches from micro tubules and the stucture will become defective 4. a. prevented the transmission of nerve impulse b. destroys neurological pathways therefore nerve impulse can not move 5. a. 1. Cerebral cortex 2. Hippocampus 3. Centripetal movement (towards centre of brain) Progression does not correspond to symptoms b. 1. Begin in hippocampus- controls memory and learning 2. Centrifugal movement Causes atrophy- global dysfunction Progressions of lesions reflected in symptoms over time.

Question 35

Identify the symptoms experienced in Alzheimer's disease in the early stages middle stages and late stages

Answer 35

Early stages Memory loss for recent events, difficulty problem-solving difficulty with complex tasks and difficulty making sound judgement Middle stages Increased poor judgement and deepening confusion great memory loss needing help with the daily activities forgetting details of personal history and wondering around Late stages Loss of ability to communicate daily assistance with eating dressing self-care tasks and decline and physical ability

Question 36

what is Parkinson's disease

Answer 36

Parkinsons disease is a chronic progressive neurological disease linked to decreased dopamine production in the brain which causes slowness of movement and impaired balance

Question 37

1 what causes parkinsons disease 2 what are the normal functions of the neurotransmitter dopamine 3 how does the the neurotransmitter of dopamine work in people with parsons disease 4 what are the effects signs and symptoms 5 what are the medical treatments (mechanical chemical and biological)

Answer 37

1 Dopamine producing nerve cells in the brain gradually degrade or die. Many of these cells are located in the Basal Ganglia (middle of the brain) and are associated with voluntary movements. 2 Dopamine: regulates motor neurons to ensure movement is executed in a smooth and controlled manner. 3 Decreased levels of dopamine: nerve impulses are delayed and uncoordinated leading to issues with movement. 4 Difficulties controlling movement, Pain, Depression, Memory problems, Sleep issues, Rigidity of muscles, Tremors, Changes in speech, Changes in walking gait, Slowly progresses over time. 5. Medications to boost dopamine (chemical), neurosurgery (mechanical) , cell replacement theory (biological)

Question 38

Explain the control of involuntary movement (somatic)

Answer 38

Step one think about the movement - Neurons devise plan for muscles contraction - sequence and intensity is planned - information is sent to primary motor area Step to initiate movement - in primary motor area and upper motor neuron is stimulated - nerve impulse is transmitted down the spinal-cord as moves past the cerebellum information is provided for smooth coordinated movement Step three movement Upper motor neuron passes impulse to lower motor neuron impulse travels directly to skeletal muscle voluntary movement occurs

Question 39

``` provide the structural features and functions of the .... cerebrum cerebral cortex frontal lobe corpus callosum thalamus hypothalamus putiitarry glad pons spinal cord cerebellum medulla oblongata ```

Answer 39

Cerebrum allows for voluntary control each hemisphere is not identical the largest structure of the brain Cerebral cortex thick grey matter allows for thinking reasoning memory and awareness of surroundings Frontal lobe allows for thinking and problem-solving emotions personality and language and control of movement Corpus callosum a large bundle of nerve fibres that connect the two hemispheres allows for communication between the two hemispheres Thalamus 3 cm in size 04 maths shape or sensory impulses passes the thalamus besides from smell allows for recognition of stimuli Hypothalamus lies in the middle of the brain controls bodily activity maintains homeostasis allows for regulation of heart rate BP and digestive juices releases growth hormones Pituitary gland ductless below the hypothalamus secrete hormones directly into the bloodstream and produces hormones required for various bodily functions Pons part of the brain stem a message station which directs impose allows for hearing and taste sensation Spinal cord roughly cylindrical Carrie sent through a Imports up to the brain and motor impulse down to the brain allows for reflexes to occur Cerebellum lies under the rear part of the cerebrum controls posture balance and find coordination of voluntary movement Medulla oblongata Communication of spinal-cord regulates reflexes of swallowing sneezing and vomiting

Question 40

What effects did the synthetic and the parasympathetic nervous system have on the following bodies organs Heart, lungs, stomach and intestines, liver, iris of the eye, sweat glands, blood vessels of skin, urinary bladder, adrenal medulla

Answer 40

Affect of sympathetic stimulation Heart: increased heart rate and strength of contraction Lungs: dilates bronchioles Stomach and intestines: decreased movement Liver: increased breakdown of glycogen and release of glucose Iris of the eyes: dilate pupils Sweat glands: increases sweat secretion Blood vessels: constricts skin vessels dilate skeletal muscle vessels and constricts internal organs except for heart and lungs Urinary bladder: relaxes muscles of wall Adrenal medulla: stimulates hormone secretion Affect on parasympathetic stimulation Heart: decreases heart rate and strength of contraction lungs: constructs bronchioles stomach and intestine's: increases movement Liver: increases uptake of glucose and synthesis of glycogen iris of the eye: constricts pupils sweat glands: no affect slavery glands: increases secretion of Silvia blood vessels little to no affect skin no effect to the muscles and little too no effect to the internal organs urinary bladder constricts muscles of wall adrenal medulla: no effect

Question 41

During flight or flight response the body prepares it self increased activity outline the ways the body changes when it prepares for these particular times

Answer 41

Increased heart rate and force of contraction of the heart increases, blood vessels dilate in organs involved in strenuous activity, blood vessels constrict and organs not involved in activity, airway in lungs dilate and rate of depth of breathing increases, blood glucose levels rise because liver convert small glycogen into glucose, secretion of sweat glands increase, adrenal medulla it releases the hormones adrenaline and noradrenaline Owen which intensify and prolong the above responses

Question 42

comparing the endocrine and nervous system explain the nature of messages, transportation of messages , cells affected, types of responses, the time taken to respond and duration

Answer 42

endocrine nature of messages/ hormones transportation of messages/ via blood stream cells affected/ all body cells types of responses/ genral wide spread the time taken to respond/ seconds too days duration/ long lasting after the stimulus stops nervous nature of messages/ electrical impulse and neurotransmitters transportation of messages/ along membrane of neurons cells affected/ muscles glands and other neurons types of responses/ local and specific the time taken to respond/ rapid in mili seconds duration/ brief stops after the stimulus stops

Question 43

Provide a definition for cell replacement therapy and tissue engineering

Answer 43

Cell replacement therapy is the replacement of damaged cells with healthy ones Tissue engineering is the rebuilding of damaged tissue by the use of biology medicine and engineering

Question 44

what are the functions of thermoreceptors osmoreceptors chemoreceptors touch receptors and pain receptors

Answer 44

thermo receptors: are able to respond to heat and cold they are found in the skin and the hypothalamus osmo receptors: located in the hypothalamus detect changes to the osmotic pressure (concentration of substance dissolved in the water) chemo receptors: present in the nose and mouth they determine particular chemicals give us sensitivity to odours and taste touch receptors: also known as Mechanoreceptors and pressure receptors can I found on the surface of the skin lips they respond to very light touch Pain receptors: Also known as nociceptors stimulated by damaged tissues and they occur in most organs but not the brain