Nervous system Flashcards
Describe the structure of the nervous system.
The nervous system is divided into two major divisions:
- The central nervous system = including the brain and the spinal cord,
- The peripheral nervous system = including the nerves outside the central nervous system.
Discuss the organisation of the nervous system.
An intricate network of billions of neurons and even more neuroglia. Organized into two main subdivisions: The central nervous system and the peripheral nervous system.
Identify the meninges of the brain and outline their function.
Inner layer = Pia mater. Cushions the brain.
Middle layer = Arachnoid, a web-like structure filled with fluid that cushions the brain.
Tough outer layer = Dura mater - protects the brain.
Define the major sections of the spinal cord.
Cervical = C1 - C7
Thoracic = T1 - T12
Lumbar = L1 - L5
Sacral = S1 - S5
What are the two sources of blood to the brain?
-internal carotid arteries
-vertebral arteries
What are the two major functions of the PNS?
It’s two major functions are:
- To carry information from the sensory organs and internal organs to the CNS.
- To convey information between the CNS and all other parts of the body outside the brain and spinal cord.
15.2 Describe sensory nerves and motor neurons.
Sensory Nerves = Carry signals to the brain from receptors.
Motor Nerves = Carry signals from the brain to effectors.
Identify the 12 pairs of cranial nerves. (I - III)
(I)
Name = Olfactory Nerve
Components = Sensory: Axons in the lining of the nose
Function = Smell
(II)
Name = Optic Nerve
Components = Sensory: Axons from the retina of the eye
Function = Vision
(III)
Name = Oculomotor Nerve
Components = XXXX
Function = Movement of Upper eyelid and eyeball; alters the shape of the lens for near vision and contracts pupil.
Identify the types of exteroceptors, interoceptors and proprioceptors.
(These send signals to the ANS - automatic nervous system)
Exterceptors = detect info outside the body.
Interoceptors = detect info inside the body about interorgans.
Proprioception = detects info about movement and pressure.
16.1 Describe the main functions of the ANS.
It regulates involuntary physiologic processes including heart rate, blood pressure, respiration, digestion, and sexual arousal.
16.2 Discuss the functions of the somatic neurons to the ANS neurons.
The somatic nervous system connects the central nervous system with the body’s muscles and skin.
To control voluntary movements and reflex arcs, while also helping us process the senses of touch, sound, taste, and smell
16.3 Describe a simple reflex arc.
Sensory neuron detecting response from receptor (like heat), sends signal through the relay neuron to the control centre, which will send a signal through the motor neuron to the effector (e.g lifting the hand of the heat)
Identify the 12 pairs of cranial nerves. (IV -VII)
(IV)
Name = Trochlear Nerve
Components = Axons of somatic motor neurons stimulate the superior oblique muscles.
Function = Movement of the eyeball
(V)
Name = Trigeminal Nerve
Components = XXXX.
Function = Touch, pain and temperature sensations and muscle sense (proprioception)
(VI)
Name = Abducens Nerve
Components = Motor: Axons of somatic motor neurons that stimulate the lateral rectus muscles.
Function = Movement of the eyeball.
(VII)
Name = Facial Nerve
Components =
-Sensory part: Axons from the taste buds on the tongue and axons from proprioceptors in muscles of the face and scalp.
- Motor Part: Axons of somatic neurons that stimulate facial, scalp and neck muscles, plus parasympathetic axons that stimulate lacrimal (tear) glands and salivary glands.
Function =
- Taste: Muscle sense (proprioception); touch, pain and temperature sensations
- Facial Expressions: secretion of tears and saliva.
Identify the 12 pairs of cranial nerves. (VIII -X)
(VIII)
Name = Vestibulocochlear nerve
Components =
- Vestibular branch, sensory: Axons from semicircular canals and utricle (organs of equilibrium).
- Cochlear branch, sensory: Acxons from the spiral organ (of hearing)
Function = Equilibrium - Vestibular branch
Hearing - Cochlear branch
(IX)
Name = Glossopharyngeal Nerve
Components =
- Sensory Part: Axons from taste buds and somatic sensory receptors on the part of the tongue, from proprioceptors in some swallowing muscles, and from stretch receptors in the carotid sinus and chemoreceptors in the carotid body.
Motor part: Axons of somatic motor neurons stimulate the swallowing muscles of the throat, and parasympathetic axons stimulate the salivary gland.
Function =
Sensory part: Taste and somatic sensations (touch, pain, and temperature) from the tongue; muscle sense (proprioception) in some swallowing muscles; monitoring blood pressure; monitoring oxygen and carbon dioxide in the blood to regulate breathing.
Motor Part - Swallowing, speech, secretion of saliva
(X)
Name = Vagus Nerve
Components =
- Sensory Part: Axons from taste buds in the pharynx (throat) and epiglottis; proprioceptors in the muscles of the neck and throat from stretch receptors; chemoreceptors in the carotid sinus and carotid body from chemoreceptors in the aortic body; and visceral sensory receptors in most organs of the thoracic and abdominal cavities.
- Motor Part: Axons of somatic motor neurons that stimulate skeletal muscles of the throat and neck plus parasympathetic axons that supply smooth muscle in the airways, oesophagus, stomach, small intestine, most of the large intestine, and gallbladder; cardiac muscle in the heart; and glands of the gastrointestinal tract,
Function =
- Sensory Part: taste and somatic sensations (touch, pain, temperature) from the pharynx and epiglottis; monitoring of blood pressure, oxygen and CO2 in the blood to regulate breathing; sensations from visceral organs in the thorax and abdomen.
- Motor Part: Swallowing, coughing and voice production; smooth muscle contraction and relaxation in organs of the gastrointestinal tract; slowing of the heart rate; secretion of digestive fluids.
Identify the 12 pairs of cranial nerves. (XI - XII)
(XI)
Name = Accessory Nerve
Components = Motor: Axons of somatic motor neurons that stimulate the sternocleidomastoid and trapezius muscles of the throat and neck
Function = Movements of the head and shoulders
(XII)
Name = Hypoglossal Nerve
Components = Motor: Axons of somatic motor neurons that stimulate muscles of the tongue
Function = Movement of tongue during speech and swallowing.
Describe what the Autonomic Nervous system is.
Part of the nervous system, regulating smooth muscle, cardiac muscle and certain glands. Although the ANS usually operates without conscious control from the cerebral cortex, it is regulated by other brain regions, mainly the hypothalamus and brain stem.
Define the Central Nervous System (CNS)
The CNS consists of the brain and spinal cord. It processes many different kinds of incoming sensory information and is the source of thoughts, emotions, and memories. Most nerve impulses that stimulate muscles to contract and glands to secrete originate from the CNS.
Define the Peripheral Nervous System (PNS)
The PNS includes all nervous tissue outside the CNS. Its components are nerves, ganglia, enteric plexuses, and sensory receptors. The PNS is divided into a somatic nervous system, an autonomic nervous system, and an enteric nervous system.
Define the Somatic Nervous System (Skeletal Nervous System).
The division of the peripheral nervous system that controls the body’s skeletal muscles.
Define the Autonomic Nervous System.
The part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart). Its sympathetic division arouses; its parasympathetic division calms.
Define the Enteric Nervous System.
The nervous system of the gastrointestinal tract. It controls secretion and motility within the GI tract and is linked to the central nervous system.
Define a Nerve.
A bundle of hundreds to thousands of axons plus associated connective tissue and blood vessels that lie outside the brain and spinal cord.
Define a Cranial Nerve.
Cranial nerves are the nerves that carry sensory input and motor output for the head and neck region. There are 12 pairs of cranial nerves.
Define a Spinal Nerve.
Spinal nerves are a bundle of nerve fibers attached to the spinal cord. They convey sensory information from the body and carry messages to muscles and glands.
There are 31 pairs of spinal nerves.
Define Ganglia.
Ganglia are small masses of nervous tissue located outside the brain and spinal cord. They consist primarily of neuron cell bodies and are closely associated with cranial and spinal nerves.
Define Enteric Plexuses.
Enteric plexuses are extensive networks of neurons located in the walls of organs of the gastrointestinal tract.
The neurons of these plexuses help regulate the digestive system.
Define Sensory Receptors.
Structures of the nervous system that monitor changes in the external or internal environment.
Examples include touch receptors in the skin, photoreceptors in the eye, and olfactory receptors in the nose.
Define Sensory Function.
Sensory receptors detect internal stimuli, such as increased blood acidity, and external stimuli, such as a raindrop landing on your arm. The sensory information is then carried into the brain and spinal cord through cranial and spinal nerves.
Define Integrative Function.
The nervous system integrates (processes) sensory information by analyzing and storing some of it and making decisions about appropriate responses—an activity called integration.
Define Motor Function.
Once sensory information is integrated, the nervous system may elicit an appropriate motor response by activating effectors (muscles and glands) through cranial and spinal nerves.
Stimulation of the effectors causes muscles to contract and glands to secrete.
Identify the key parts of the neuron.
Define a Soma.
The body of neurons; responsible for the health of neurons and speed of signal
Identify the key parts of the neuron.
Define Dendrites.
The input of neurons; receive electric signals.
Which type of glial cells are found in the choroid plexus and CSF?
Ependymal cells: take fluids from the body and re-secretes them as CSF
What type of glial cells makeup CNS myelination?
oligodendrocytes (white matter)
What type of glial cells makeup PNS myelination?
Schwann cells: made up of phospholipid bilayer
- can regenerate*
- variable thickness of myelin sheath
