Nervous System

Question 1

What retie 4 functions of the nervous system?

Answer 1

• It receives and processes sensory input (e.g. sight, pain, temperature)
• Controls muscles and glands
• Maintains homeostasis by coordination of many bodily systems
• Establishes and maintains mental activity (e.g. thinking, emotions, behavior, etc.)

Question 2

What are neurons?

Answer 2

Neurons are the nerve cells. They are excitable cells which receive stimuli and conduct and transmit signals to other cells.

Question 3

What are non-neurons?

Answer 3

Non-neurons are called glial cells. They surround and wrap delicate neurons to support and protect them.

Question 4

What is a synapse?

Answer 4

Synapses are the contact between 1 nerve and another nerve, muscle, gland, or sensory receptor. They transmit signals from one cell to another, through the release of neurotransmitters from the axon terminal into the synapse.

Question 5

Neurons receive _____ and ______ & transmit signals to other neurons or organs by __________ _________

They can live and function for over 100 years, but lose the ability to ______ once functioning. Neurons have a high ________ rate so need lots of _______ & nutrients. They form complex networks

Answer 5

Neurons receive STIMULI and INTEGRATE & transmit signals to other neurons or organs by ELECTROCHEMICAL CONDUCTION

They can live and function for over 100 years, but lose the ability to DIVIDE once functioning. Neurons have a high METABOLIC rate so need lots of OXYGEN & nutrients. They form complex networks

Question 6

There are 3 parts to a neuron- Describe them (cell body, axon, dendrite)

Answer 6

• Cell body – contains nucleus, with most residing in the central nervous system
• Axon – single long thin process or nerve fibers which conduct signals away from the cell body and vary in length from millimeters to over 1m
• Dendrite – short & can be highly branched, receives info from other neurons & the environment and transmits to the cell body

Question 7

Functional classification splits neurons into 3 groups (sensory, motor, or interneurons)- describe them.

Answer 7

• Sensory, or afferent: action potentials towards the CNS from organs
• Motor, or efferent: action potentials away from CNS towards organs
• Interneurons, or association neurons: from one neuron to another within the CNS

Question 8

Structural classification splits neurons into 3 groups(multipolar, bipolar, and unipolar)- describe them.

Answer 8

• Multipolar: these have many dendrites and 1 axon, and make up most neurons in the CNS
• Bipolar: these have 1 dendrite and 1 axon, and are the sensory neurons in the nose and retina of the eye
• Unipolar: these have a single process that divides into 2 branches- 1 to the CNS and 1 to the PNS. The part that extends to the periphery has dendrite like sensory receptors. Most sensory neurons are unipolar.

Question 9

What do glial cells do?

Answer 9

Glial cells support and protect neurons. They produce cerebrospinal fluid, and form insulating layers around axons called myelin. They form a permeable barrier between blood and neurons, and eliminate invading bacteria/viruses and toxins.

Question 10

Glial cells account for over half of the _____’s weight. In part of the brain there is often 10-50x more _______ than neurons. Glial cells can ______ and ________. Gliomas are the most common type of brain ________.

There are lots of types of neuroglia: Astrocytes, Microglia, Satellite cells, Oligodendrocytes, Ependymal cells, Schwann cells.

Answer 10

Glial cells account for over half of the BRAIN’s weight. In part of the brain there is often 10-50x more NEUROGLIA than neurons. Glial cells can DIVIDE and MULTIPLY. Gliomas are the most common type of brain TUMOR.

There are lots of types of neuroglia: Astrocytes, Microglia, Satellite cells, Oligodendrocytes, Ependymal cells, Schwann cells.

Question 11

Nervous tissue in the peripheral and central nervous systems can be organised into grey matter and white matter.
What is grey matter?

Answer 11

Grey matter is the neuron cell bodies and their short dendrites, synapses, and glia. In the central nervous system grey matter is found on the surface of the brain (cortex) and clusters deeper in the brain (nuclei). In the peripheral nervous system grey matter is called ganglion.

Question 12

Nervous tissue in the peripheral and central nervous systems can be organised into grey matter and white matter.
What is white matter?

Answer 12

White matter is the axons in bundles with their myelin sheaths. Myelin protects and insulates axons from one anther and speeds up signal transmissions. Within the central nervous system, white matter forms tracts. In the peripheral nervous system, white matter is called nerves.

Question 13

What is the function of the CNS?

Answer 13

The central nervous system processes, integrates, stores, and responds to information from the peripheral nervous system.

Question 14

The brain is the ______ _______ for the body’s functions. It has the ability to adapt to the environment, which is called ____ _____. The brain is contained within the ______ _______.

Answer 14

The brain is the CONTROL CENTRE for the body’s functions. It has the ability to adapt to the environment, which is called BRAIN PLASTICITY. The brain is contained within the CRANIAL CAVITY.

Question 15

The brainstem connects the ______ ______ to the _____. it is responsible for ______ and wakefulness. The cranial nerves (PNS) come off the brainstem. It performs essential functions such as _______ (reticular formation) and so damage to just a small area can cause death.

Answer 15

The brainstem connects the SPINAL CORD to the BRAIN. it is responsible for REFLEXES and wakefulness. The cranial nerves (PNS) come off the brainstem. It performs essential functions such as CARDIORESPIRATORY (reticular formation) and so damage to just a small area can cause death.

Question 16

The brainstem can be split into 3 sections: the midbrain, pons, and medulla oblongata. Describe them.

Answer 16

The midbrain, or mesencephalon, is the smallest, most superior region of the brainstem. It contains the visual reflex center and part of the auditory pathway.

The pons is between the midbrain and medulla oblongata. It relays information between the cerebrum and cerebellum. It is the site of more reflex centers and contains the sleep and respiratory centers.

The medulla oblongata is around 3cm long and is the most inferior part of the brain. It is continuous with the spinal cord, and regulates essential reflexes.

Question 17

The _______ is attached to the brainstem posteriorly to the pons. It controls muscle _______, tone, _______ and posture. It has a rigid surface (______) and is split into 2 lateral hemispheres, each split into an _______ and _______ lobe. It communications with the CNS through 3 large tracts called cerebellar _______. Internally white matter is branched with grey matter between. The cerebellum makes up 10% of the brain’s volume, and has 50% of it’s ________.

Answer 17

The CEREBELLUM is attached to the brainstem posteriorly to the pons. It controls muscle MOVEMENT, tone, BALANCE and posture. It has a rigid surface (FOLIA) and is split into 2 lateral hemispheres, each split into an ANTERIOR and POSTERIOR lobe. It communications with the CNS through 3 large tracts called cerebellar PEDUNCLES. Internally white matter is branched with grey matter between. The cerebellum makes up 10% of the brain’s volume, and has 50% of it’s NEURONS.

Question 18

The diencephalon is the part between the brainstem and the cerebrum. It contains the thalamus, subthalmus, epithalmus, and hypothalamus. Describe each part.

Answer 18

The thalamus is the largest part of the diencephalon. It is the major sensory relay center, and influences mood and movement. The subthalmus is small and inferior to the thalamus, and plays a role in motor functions. The epithalmus responds to olfactory stimulation and contains the pineal gland, which plays a role in the onset of puberty. The hypothalamus is the major control centre for maintaining homeostasis. It regulates neuroendocrine function and autonomic function.

Question 19

What are each hemisphere of the cerebrum for? What connects the 2?

Answer 19

It is split into 2 hemispheres- one for conscious thought and one for motor and sensory processing, each of which has many lobes. The corpus collosum connects the 2 hemispheres of the cerebrum

Question 20

What are gyri and what is their purpose?

Answer 20

The surface of the cerebrum is folded into gyri which increases surface area. There is a similar pattern in most people.

Question 21

The grooves between the gyri are called ______. There are 3 main cerebral sulci and fissures. The _________ fissure separates the 2 hemispheres. The lateral fissure separates the _______ lobe from frontal and _______ lobes. The central _____ separates the frontal and parietal lobes. Anteriorly is the precentral gyrus, which is the primary ______ cortex. Posteriorly is the postcentral gyrus, which is the primary ______ cortex.

Answer 21

The grooves between the gyri are called SULCI. There are 3 main cerebral sulci and fissures. The LONGITUDINAL fissure separates the 2 hemispheres. The lateral fissure separates the TEMPORAL lobe from frontal and PARIETAL lobes. The central SULCUS separates the frontal and parietal lobes. Anteriorly is the precentral gyrus, which is the primary MOTOR cortex. Posteriorly is the postcentral gyrus, which is the primary SENSORY cortex.

Question 22

The cerebral lobes are named according to the skull bone overlying them. What are each of the lobes for? (frontal, parietal, occipital, and temporal)

Answer 22

The frontal lobe is for voluntary motor function, aggression, sense of smell, mood, personality, abstract thought, and judgment.

The parietal lobe processes sensory information, except smell, hearing, and vision.

The occipital lobe processes visual input.

The temporal lobes processes hearing, speech comprehension and visual recognition.

Question 23

Meninges are a membrane which surround the brain and spinal cord, to protect them. There are several membranes/meninges: the dura matter, arachnoid, and pia matter. Describe each of them.

Answer 23

The dura matter is superficial and thick. It is separated in the spine from vertebrae by the epidural space, which contains nerve roots, blood vessels and adipose tissue. Dura matter around the brain adheres tightly to the cranium so there is no real epidural space. The arachnoid is the next deeper meningeal membrane, and is thin. The space between the dura matter and arachnoid membranes is called the subdural space. The pia matter is the deepest membrane and is bound very tightly to the spinal cord and brain

Question 24

What is the subarachnoid space?

Answer 24

The subarachnoid space is between the arachnoid and pia matter. It contains blood vessels and cerebrospinal fluid.

Question 25

What is meningitis? What are the symptoms? How can symptoms appear in children? How can it be tested? How can it be treated?

Answer 25

Meningitis is an inflammation of the protective meninges membranes, and may be caused by infection with viruses, bacteria, or other microorganisms. Symptoms of meningitis include headache and neck stiffness, fever, confusion, or altered consciousness, vomiting, and inability to tolerate light or loud noises, Sometimes, especially in children, only nonspecific symptoms may be present, such as irritability and drowsiness. A presence of a rash may indicate meningitis caused by meningoccal bacteria. A lumbar puncture used to extract a sample of cerebrospinal fluid is used to diagnose or exclude meningitis. Antibiotics, and sometimes antiviral drugs, are used to treat meningitis. Treatment must be prompt, or can lead to serious long-term consequences such as deafness, epilepsy, and cognitive deficits.

Question 26

Cerebrospinal fluid (CSF) is a clear fluid similar to blood serum. What is the function of CSF?

Answer 26

It bathes the brain & spinal cord so provides protective cushion, and provides buoyancy so the brain floats in the cranial cavity without directly resting on the skull or dura matter. It also protects the brain from shock of rapid head movements, and provides the CNS with some nutrients

Question 27

the brain needs lots of blood for normal function. It accounts for only 2% of the body’s weight, but receives ______% of blood. Arteries supplying the brain lie in the ________ space. Small branches leave this space and enter the ___ ______ where they branch further. Blood reaches the brain through internal carotid and vertebral arteries. The basilar artery is where the vertebral arteries ___. The internal carotid and vertebral arteries from the cerebral artery circle (circle of Willis). The anterior, middle, and posterior cerebral arteries supply the _____ ______.

Answer 27

the brain needs lots of blood for normal function. It accounts for only 2% of the body’s weight, but receives 15-20% of blood. Arteries supplying the brain lie in the SUBARACHNOID space. Small branches leave this space and enter the PIA MATTER where they branch further. Blood reaches the brain through internal carotid and vertebral arteries. The basilar artery is where the vertebral arteries JOIN. The internal carotid and vertebral arteries from the cerebral artery circle (circle of Willis). The anterior, middle, and posterior cerebral arteries supply the CEREBRAL CORTEX.

Question 28

What is an open brain injury? What is a closed brain injury?

Answer 28

Open brain injuries are when some of the cranial contents are exposed. This involves a fracture or hole in the skull. CSF may leak from the nose or ear, meaning there is risk of meningitis. Closed brain injuries occur when the cranial cavity remains intact. These are more common, and often occur as a result of the head striking a hard surface or object. This causes brain trauma at the site of impact or the opposite side.

Question 29

What is concussion?

Answer 29

Concussion is the most common brain injury, causing brief unconsciousness, confusion, post-traumatic amnesia, headache, and/or nausea. This causes immediate but transient impaired neural function, e,g. blurred vision.

Question 30

Describe a stroke

Answer 30

A stroke is a rapid loss of brain function(s). this can be sue to ischaemia (lack of blood flow) or haemorrhage (leakage of blood). Strokes are the leading cause of adult diability in Europe. It can result in an inability to move one side of the body, an inability to understand or formulate speech, or an inability to see one side of the visual field. Strokes can cause permenant neurological damage, complications, and death. Risk factors for strokes include old age, hypertension, previous stroke or TIA, diabetes, high cholesterol, smoking, etc.

Question 31

The spinal cord extends from the foramen magnum (base of the brain) to the 2nd _____ vertebrae level. It is ______ than the vertebral column as it doesn’t grow as much during development. The spinal cord is divided into cervical, thoracic, lumbar, and sacral segments, named according to the portion of the vertebral column that ______ enter/exit. The spinal cord has a larger diameter _______ than _______. There are 2 enlargements in the spinal cord where the nerves supplying the upper and lower limbs enter and leave. The spinal cord gives off __ pairs of spinal nerves. They carry ______, motor, and ________ information between the brain and body. It is the communication link between the brain and the _________ nervous system. It integrates incoming information and produces responses through _______.

Answer 31

The spinal cord extends from the foramen magnum (base of the brain) to the 2nd LUMBAR r vertebrae level. It is SHORTER than the vertebral column as it doesn’t grow as much during development. The spinal cord is divided into cervical, thoracic, lumbar, and sacral segments, named according to the portion of the vertebral column that NERVES enter/exit. The spinal cord has a larger diameter SUPERIORLY than INFERIORLY. There are 2 enlargements in the spinal cord where the nerves supplying the upper and lower limbs enter and leave. The spinal cord gives off 31 pairs of spinal nerves. They carry SENSORY, motor, and AUTONOMIC information between the brain and body. It is the communication link between the brain and the PERIPHERAL nervous system. It integrates incoming information and produces responses through REFLEXES.

Question 32

The spinal cord is divided into cervical, thoracic, lumbar, and sacral segments and each segment of the spinal cord has a different function. What are they?

Answer 32

The cervical segment is for breathing, head and neck movement, heart rate, and upper limb movements. The thoracic segment is for sympathetic tone and trunk stability. The lumbar segment is for lower limb movement. The sacral segment is for bowel and bladder control.

Question 33

What are the 2 enlargements in the spinal cord for?

Answer 33

It is where the nerves supplying the upper and lower limbs enter and leave.

Question 34

Damage to the spinal cord can disrupt ascending tracts to the brain or descending tracts - what is the result of each?

Answer 34

Damage to the spinal cord can disrupt ascending tracts to the brain resulting in loss of sensation, or disrupt descending tracts from the brain resulting in loss of motor functions.

Question 35

What can spinal cord injury can be classified by?

Answer 35

Spinal cord injury can be classified by the vertebral level where the injury occurred, whether the entire cord or only a portion is damaged at that level, and the mechanism of injury.

Question 36

Where do the most severe spinal cord injuries occur? What is the result of a spinal cord injury in this area? What is the result of spinal cord injury elsewhere?

Answer 36

Injuries above T1 are most severe and can result in paralysis of all four limbs with abdominal and chest muscles also affected. Injuries at or below T1 can result in varying degrees of paralysis of legs (paraplegia) and abdomen, while retaining full function of the upper limbs.

Question 37

What is a spinal block? Why would you use spinal block over an epidural.

Answer 37

Spinal anaesthesia/spinal block is when drugs are injected into the subarachnoid space to prevent pain sensations in the lower body. Spinal drugs go straight into the CSF so anaesthesia is quicker and stronger than an epidural.

Question 38

What is a lumbar puncture?

Answer 38

A lumbar puncture/spinal tap is when CSF is removed from subarachnoid space to examine for infections (meningitis), presence of blood (haemorrhaging), and CSF pressure.

Question 39

What is the function of the PNS?

Answer 39

The peripheral nervous system detects stimuli and transmits information to and from the CNS.

Question 40

What does the sensory/afferent division of the PNS do?

Answer 40

Sensory, or afferent, conveys information to the CNS from sensory receptors throughout the body. There are 2 types of fibers: somatic afferent fibers, which are responsible for impulses from skin, skeletal muscles, and joints: and visceral afferent fibers, which are responsible for impulses from organs.

Question 41

What does the motor/efferent division of the PNS do?

Answer 41

Motor, or efferent, conveys information from the CNS to the effector organs. There are 2 subdivisions: somatic and autonomic. Somatic is from the CNS to skeletal muscles, and controls voluntary movement, under conscious control. Autonomic is the visceral motor fibers regulating the activity of smooth muscle, cardiac muscle, and glands. This is involuntary control.

Question 42

Peripheral nervous tissue is made up of sensory receptors, nerves, ganglia, and plexuses. Describe each type of tissue.

Answer 42

Sensory receptors are the endings of neurons that detect sensory stimuli in the environment, e.g. heat, pain, light, and sound. They are located in the skin, muscles, internal organs, and special organs like eyes. Sensory receptors send signals back to the CNS along afferent sensory fibers. Nerves are bundles of axons and their sheaths (white matter) and connects the CNS to sensory receptors, muscles, and glands. Ganglia is a collection of neuron cell bodies associated with nerves in the PNS. It is the grey matter located outside the CNS. Plexuses are extensive networks of nerves outside the CNS.

Question 43

Where in the CNS do the cranial nerves and spinal nerves originate?

Answer 43

The nerves of the PNS originate in the CNS- cranial nerves originate from the brain, and spinal nerves originate from the spinal cord.

Question 44

Describe Facial (Bell's) Palsy.

Answer 44

Facial (Bell’s) Palsy involves facial nerve VIII causing unilateral paralysis of facial muscles, causing a side of the face to droop. Damage to the Vagus X nerve causes difficulty swallowing. Damage to the Olfactory I nerve causes loss of sense of smell. Damage to the Abducens (VI) nerve can cause double vision.

Question 45

What 3 things does each of the spinal nerves consist of ?

Answer 45

a bundle of axons, glial support cells (Schwann cells) and a myelin sheath.

Question 46

Name the 2 types of spinal nerve rami.

Answer 46

dorsal/posterior rami and ventral/anterior rami.

Question 47

Ventral/anterior rami are found in the upper and lower limbs and lateral and ventral trunk- these don’t go straight to the tissues they supply, but form networks/________. The ventral rami are distributed in 2 ways: 1) the thoracic ventral rami form _______ nerves which extend along the inferior margin of the ribs, and ________ intercostal muscles and skin over the thorax, and 2) all other ventral rami form _ major plexuses. These nerves arise from plexuses after a series of _______. These usually have ____ from more than 1 spinal nerve. Nerves from lower segments descend some distance in the ______ canal before they exit. They arise as rootlets, and join to form ____. The _____ root is afferent/sensory. The _______ root is efferent/motor. The roots unite to form a ____ _____.

Answer 47

Ventral/anterior rami are found in the upper and lower limbs and lateral and ventral trunk- these don’t go straight to the tissues they supply, but form networks/PLEXUSES. The ventral rami are distributed in 2 ways: 1) the thoracic ventral rami form INTERCOSTAL nerves which extend along the inferior margin of the ribs, and INNERVATE intercostal muscles and skin over the thorax, and 2) all other ventral rami form 5 major plexuses. These nerves arise from plexuses after a series of BRANCHING. These usually have AXONS from more than 1 spinal nerve. Nerves from lower segments descend some distance in the VERTEBRAL canal before they exit. They arise as rootlets, and join to form ROOTS. The DORSAL root is afferent/sensory. The VENTRAL root is efferent/motor. The roots unite to form a SPINAL NERVE.

Question 48

Which major plexus is "ventral rami of C1–C4, and innervates the neck muscles and skin of the neck and posterior head. One of the most important nerves from the cervical plexus is the Phrenic Nerve which innervates the diaphragm"?

Answer 48

Cervical plexus

Question 49

Which major plexus is "C5–T1, innervates the upper limb muscle & skin"?

Answer 49

Brachial plexus

Question 50

Which 2 major plexuses "innervates the lower limbs, lower back, lower abdomen, and hips."?

Answer 50

Lumbar plexus: L1-L4 and Sacral plexus :L4-S4, often considered together as the lumbosacral plexus.

Question 51

Which major plexus is "S5 and coccygeal nerve, innervates muscles of the pelvic floor & skin over the coccyx"?

Answer 51

Coccygeal plexus

Question 52

Describe crutch palsy

Answer 52

Crutch palsy is when prolonged use of crutches causes compression of the brachial plexus in the axilla. This commonly affects the radial nerve and so the extensor muscles.

Question 53

Describe radial nerve damage

Answer 53

Radial nerve damage causes drop wrist, and so you can’t extend your hand. This is caused by intramuscular injections into the deltoid muscle.

Question 54

Describe carpel tunnel syndrome

Answer 54

Carpal tunnel syndrome is median nerve damage, causing numbness, tingling & pain in the palms & fingers. This is due to compression of the carpal tunnel compartments due to repetitive wrist flexion (e.g. typing).

Question 55

Describe Erb's palsy

Answer 55

Erb’s Palsy is damage to Erb’s point where C5 & C6 meet. It can be damaged in difficult/breech births. Movements of the fingers will be unimpaired, as their innervation is from T1.

Question 56

What is the sciatic nerve?

Answer 56

The sciatic nerve is the tibial and common fibular nerves bound in one sheath (lumbosacral plexus). It is the largest peripheral nerve in the body.

Question 57

If you sit on hard surface for a considerable time, the _____ nerve may be compressed against the ___ ______ causing temporary “pins and needles” in the lower limbs. However, the sciatic nerve can be seriously injured, causing pain down the back of the leg. A ruptured __________ _____ or pressure from the _____ ______ ________ may compress roots of sciatic nerve, as can a hip injury, compression of the nerve, and an improperly administered injection in ___region.

Answer 57

If you sit on hard surface for a considerable time, the SCIATIC nerve may be compressed against the HIP BONE causing temporary “pins and needles” in the lower limbs. However, the sciatic nerve can be seriously injured, causing pain down the back of the leg. A ruptured INTERVERTEBRAL DISK or pressure from the UTERUS DURING PREGNANCY may compress roots of sciatic nerve, as can a hip injury, compression of the nerve, and an improperly administered injection in HIP region.

Question 58

What are dermatomes?

Answer 58

Nerves arising from each region of the spinal cord supply specific regions of the body. A dermatome is an area of skin supplied by a pair of spinal nerves.

Question 59

The somatic motor neurons innervate _______ muscle, and control _______ activities. Somatic motor neurons always have an _______ effect on muscles. Autonomic motor neurons innervate smooth muscle, _____ muscles, and glands, and controls _______ activities. It can be excitatory or inhibitory. An example is when after a meal the ANS _______ stomach activities but during exercise the ANS _____ these. The ______ nervous system is the intrinsic nervous system of the digestive system (ANS). The ANS can be further subdivided into sympathetic and parasympathetic. The ________ nervous system is active during physical activity (i.e. flight or fight). The _________ nervous system regulates resting functions (i.e. res and digest).

Answer 59

The somatic motor neurons innervate SKELETAL muscle, and control CONSCIOUS activities. Somatic motor neurons always have an EXCITATORY effect on muscles. Autonomic motor neurons innervate smooth muscle, CARDIAC muscles, and glands, and controls SUBCONSCIOUS activities. It can be excitatory or inhibitory. An example is when after a meal the ANS STIMULATES stomach activities but during exercise the ANS INHIBITS these. The ENTERIC nervous system is the intrinsic nervous system of the digestive system (ANS). The ANS can be further subdivided into sympathetic and parasympathetic. The ______ nervous system is active during physical activity (i.e. flight or fight). The _______ nervous system regulates resting functions (i.e. rest and digest).

Question 60

True or false: "Most organs receive autonomic neurons innervated by parasympathetic and sympathetic divisions." Explain why it is true/false.

Answer 60

True- Most organs receive autonomic neurons innervated by parasympathetic and sympathetic divisions. Both produce stimulatory and inhibitory effects- it is not true that sympathetic is stimulatory and parasympathetic is inhibitory. The sympathetic and parasympathetic divisions often have opposite/complementary effects. The ANS is always working, not just in "fight or flight" or "rest and digest" situations. ANS acts to maintain normal internal functions.

Question 61

Are nerves innervating cardiac muscle and muscle in the gut are primarily autonomic, somatic, or sensory neurons?

Answer 61

Sensory and autonomic

Question 62

Are nerves innervating skeletal muscles primarily autonomic, somatic, or sensory neurons?

Answer 62

sensory and somatic motor axons

Question 63

Unlike the somatic nervous system, the ANS has 2 neurons taking signal from the CNS to the effector organ. What is the pre-ganglionic neuron? What is the post-ganglionic neuron?

Answer 63

the pre-ganglionic neuron is the cell body in the CNS, and the post-ganglionic neuron is the cell body in ANS ganglia.

Question 64

Describe the similarities and differences of the autonomic nervous system, and somatic nervous system.

Answer 64

Both are part of the motor division of the PNS. Motor neurons can be somatic or autonomic. But sensory neurons are not classified as somatic or autonomic- they send information from sensory receptors to the CNS and provide information for reflexes mediated through the somatic nervous system or ANS, for example stimulation of pain receptors can initiate somatic reflexes (withdrawal reflex) and autonomic reflexes (increase heart rate). Both are part of the motor division of the PNS. Motor neurons can be somatic or autonomic. But sensory neurons are not classified as somatic or autonomic- they send information from sensory receptors to the CNS and provide information for reflexes mediated through the somatic nervous system or ANS, for example stimulation of pain receptors can initiate somatic reflexes (withdrawal reflex) and autonomic reflexes (increase heart rate).