The Structure of The Nervous System Flashcards
Anterior / rostral
Towards to nose.
from the Latin for “beak” (in Danish: “næb”)
Posterior / caudal
Towards the tail.
from the Latin for “tail”
Dorsal
The direction pointing up.
from the Latin for “back”
Ventral
The direction pointing down
from the Latin for “belly”
Bilateral symmetry
The nervous system is divided into two equal halves.
The right side of the brain and spinal cord is the mirror image of the left side.
With just a few exceptions, most structures within the nervous system come in pairs, one on the right side and the other on the left.
Midline
The invisible line running down the middle of the nervous system.
Medial
Structures closer to the midline.
E.g. the nose is medial to the eyes, and the eyes are medial to the ears
Lateral
Structures farther away from the midline.
Ipsilateral structures
Structures that are on the same side
E.g. the right ear is ipsilateral to the right eye.
Contralateral structures
Structures that are on opposite sides of the midline.
E.g. the right ear is contralateral to the left ear.
The three anatomical planes of section
- The midsagittal plane
- The horizontal plane
- The coronal plane
The midsagittal plane
Splitting the brain into equal right and left halves.
The sagittal plane
Sections parallel to the midsagittal plane.
The horizontal plane
The plane that is parallel to the ground
Could pass through both the eyes and the ears.
The coronal place
Perpendicular to the ground and to the sagittal plane
Could pass through both eyes and both ears but not at the same time
The two cerebral hemispheres are separated by …
the deep sagittal fissure
also called the longitudinal fissure
Which side of the body is the left cerebal hemisphere concerned with?
the right side of the body
Which side of the body is the right cerebral hemisphere concerned with?
the left side of the body
Which side of the body is the left side of the cerebellum concerned with?
the left side of the body
Which side of the body is the right side of the cerebellum concerned with?
the right side of the body
What is the spinal cored encased in?
The bony vertebral column
Spinal nerves
What? Exit the spinal cord? Attach the spinal cord? Dorsal and ventral?
- The spinal cord communicates with the body via the spinal nerves (part of PNS).
- They exit the spinal cord between each vertebra of the vertebal column.
- Each spinal nerve attaches the spinal cord through the dorsal and ventral root.
- The dorsal root contains axons bringing information into the spinal cord. The ventral root contains axons carrying information away from the spinal cord.
The peripheral nervous system consists of …
The somatic PNS and the visceral PNS.
The somatic PNS
- Consists of spinal nerves that innervate and collect information from the skin, muscles and joints.
- Voluntary nervous system
- Somatic motor axons: muscle contraction, derive from motor neurons in the ventral roots of the spinal cord.
- Somatic sensory axons, enter the spinal cord via the dorsal roots, cell bodies in dorsal root ganglia.
What is the visceral PNS also called?
The involuntary, vegetative or autonomic nervous system.
Visceral PNS
- Consists of neurons that innervate the internal organs, blood vessels and glands.
- Visceral sensory axons bring information about the organs to the CNS.
- Visceral motor axons command contraction and relaxation of muscles in organs
- Involuntarry system
Afferent
From the latin (“carry to”).
Bringing information into the CNS.
Efferent
From the Latin (“carry from”).
Emerging from the CNS to the internal organs.
How many cranial nerves do we have? Where do they arise from?
12 cranial nerves that arise from the brain stem.
The meninges
The collective name for the three membranes that protect the CNS in the skull and vertebral column.
The three membranes are the dura mater, the arachnoid membrane and the pia mater.
The three membranes of the meninges and the subarachnoid space
The dura mater: The outermost covering. Leatherlike consistency. Tough, inelastic bag that surrounds the brain and spinal cord.
The arachnoid membrane: Appearance and consistency like a spider web.
The pia mater: A thin membrane close to the surface of the brain. Many blood vessels that dive into the underlying brain.
The subarachnoid space: Space between the pia mater and the arachnoid membrane that is filled with cerebrospinal fluid (CSP) , a salty clear liquid.
The ventricular system
Consists of caverns and canals in the brain filled with cerebrospinal fluid.
Where is cerebrospinal fluid produced? What happens to the produced CSP?
Where: In the choroid plexus tissue in the ventricles of the cerebral hemispheres.
How: CSF flows from the ventricles to some central cavities at the core of the brain stem. Exits the ventricular system and enters the subarachnoid space through small openings located where the cerebrum attaches to the brain stem. In the subarachnoid space, CSF is absorbed by the blood vessels at special structures called arachnoid villi.
