Nervous System Flashcards
What is the neuroglia of the CNS?
Astrocytes, Ependymal cells, Microglia, Oligodendrocytes
What is the function of astrocytes?
- Forming a supporting framework for blood vessels and neurons.
- Assists in the formation of tight junctions between endothelial cells of the capillaries
- Respond to tissue damage in the CNS
What is the function of ependymal cells?
- Line the central cavities of the brain and spinal cord
What is the function of microglial cells?
- Monitor the health of surrounding neurons
- Phagocytose microorganisms, infection, trauma or inflammation
What is the function of oligodendrocytes?
- Cover axons which form an insulating sheath around them
What is the neuroglia of the PNS?
- Schwann cells
- Satellite cells
What is the function of Schwann cells?
- Form myelin sheath around axons to insulate
- Also called neurolemmocytes
What is the function of satellite cells?
- Provide support and nutrition to cell bodies in ganglia
- Protect cell bodies from harmful substances
What are the characteristics of the cell membrane that allow a membrane potential to be generated?
- Differences in ionic concentration across the cell membrane (particularly sodium and potassium).
- Permeability of the cell membrane to ions.
What are non-gated ion channels?
Ion specific channels. Also known as leak channels. The cell membrane has more K+ leak ion channels compared to Na+ leak channels.
What are gated ion channels?
Channels that require signals to open them. Ligand-gated, voltage-gated, and other-gated.
What is depolarisation?
When the membrane potential becomes more positive
What is hyperpolarisation?
When the membrane potential becomes more negative
What is repolarisation?
When the membrane potential returns to normal
What is graded potential?
Short-lived, localised changes in membrane potential. Often occurs in dendrites or the cell body of a neuron. Graded potentials are decremental meaning they are not able to transfer information over long distances.
What is a reflex?
An automatic response to a stimulus. Can be somatic or autonomic, and are homeostatic.
What are the types of reflexes?
Stretch (monosynaptic), golgi tendon, withdrawal
What are the five regions of the spinal cord?
Cervical, thoracic, lumbar, sacral, and coccygeal
What many pairs of spinal nerves are there?
31
How many pairs of cranial nerves are there?
12
What is the function of the meninges?
Protects the CNS and its blood vessels.
Contains cerebrospinal fluid
Forms partitions in the skull
What are the layers of the meninges?
Dura mater, arachnoid mater, pia mater
Describe the dura mater
Surround the subdural space, which contains serous fluid
Describe the arachnoid mater
Surround the subarachnoid space, which contains cerebrospinal fluid and blood vessels.
Describe the pia mater
Has many small blood vessels
What is the structure of a nerve?
Endoneurium, perineurium, epineurium
What is the location of the endoneurium?
The innermost layer. Surrounds each axon and its associated Schwann cells
What is the location of the perineurium?
Middle layer. Surround a group of axons or a new fascicle/
What is the location of the epineurium?
Surrounds a group of fascicles.
What is the function of the midbrain?
Receives visual, auditory and tactile sensory input generating reflex movements of the head, eyes and body.
Controlling the movement of the eye
What is the function of the medulla oblongata?
Autonomic reflex centre maintaining body homeostasis.
Contains the cardiovascular centre, respiratory centre, and a centre of other reflexes.
What is the function of the pons?
Respiratory centre, sleep centre (REM).
Pons = bridge
Contains conduction tracts: longitudinal from spinal cord to higher brain centres, transverse tracts from the cerebrum and cerebellum.
What is the function of the cerebellum?
Controls locomotion, fine motor control, posture and balance
What structures does the diencephalon house?
Thalamus, subthalamus, epithalamus, hypothalamus
What is the function of the thalamus?
Sensory relay centre for all senses except for smell. Regulates mood, memory, and strong emotions.
What is the function of the hypothalamus?
Maintains homeostasis, regulates heart rate, digestion, sex drive, mood, motivation, emotions and the sleep-wake cycle. Controls muscles in swallowing and body temperature.
Where is the longitudinal fissure?
Separating left and right hemispheres
Where is the lateral fissure?
Separates temporal lobe from the rest of the cerebrum.
Where is the central sulcus?
Separates frontal lobe from parietal lobe
Where is the precentral gyrus?
Primary somatic motor cortex
Where is the postcentral gyrus?
Primary somatosensory cortex
Describe the dura mater in the brain
Consists of the periosteal dura, dural venous sinus, meningeal dura and the subdural space.
The dural venous sinus surrounds the venous blood and dural folds. The subdural space consists of the serous fluid.
Describe the arachnoid mater in the brain
Consists of the subarachnoid space which surrounds the cerebrospinal fluid and blood vessels.
Describe the pia mater in the brain
Has many small blood vessels.
Describe the ventricles in the brain
Lined with ependymal cells First and second: lateral ventricle Third ventricle Fourth ventricle Ventricles produce cerebrospinal fluid
What is the function of CSF?
Protects the brain and spinal cord from trauma and provides buoyancy to the brain. Most of CSF is produced by the choroid plexus of the ventricles. CSF composition is similar to blood plasma but with less proteins and different ionic concentration.
What is the anatomy of the sympathetic division of the autonomic nervous system?
Thoracolumbar division.
- T1 to L2
What is the anatomy of the parasympathetic division of the autonomic nervous system?
Craniosacral division
- S2 to S4
- Cranial nerve nuclei
What are the general functions of both divisions of the ANS?
Opposite effects on:
- heart rate
- blood pressure
- airways in lungs
- digestive tract
- glands
- pupil of the eye
Differences between sympathetic and parasympathetic
Sympathetic (e division)
- exercise, emergency, excitement, embarassment
Parasympathetic (d division)
- digestion, defecation and diuresis
