Lecture 2 - The Anatomy of the Nervous System Flashcards
(42 cards)
What is the gross neuroanatomy?
Anatomical features of the nervous system that are apparent to the naked eye.
The gross view of the entire human nervous system reveals the basic division between the CNS and PNS.
What does the Peripheral Nervous System consist of?
The PNS consists of nerves that extend throughout the body.
- MOTOR NERVES: info from the CNS to muscles and glands
- SENSORY NERVES: info from the body to the CNS.
What are the two systems of the PNS?
The various nerves of the body are divided into two distinct systems:
SOMATIC NERVOUS SYSTEM: cranial and spinal nerves that interconnect the brain and the major muscles and sensory systems of the body.
AUTONOMIC NERVOUS SYSSTEM: nerves that connect primarily to the viscera (internal organs)
What are the 12 cranial nerves?
- Olfactory - Smells (SENSORY)
- Optic - Vision (SENSORY)
- Oculomotor - moves eye (MOTOR)
- Trochlear - moves eye (MOTOR)
- Abducens - moves eye (MOTOR)
- Trigeminal - Face, sinuses, teeth (BOTH)
- Facial - tongue, facial muscles (BOTH)
- Vestibulocochlear - Hearing + balance (SENSORY)
- Glossopharyngeal - Mouth sensations (BOTH)
- Vagus - info from internal organs (BOTJH)
- Spinal Accessory - Neck muscles (MOTOR)
- Hypoglossal - Tongue muscles (MOTOR)
What are spinal nerves made out of and where are they?
One member of each pair serves each side of the body—emerge through regularly spaced openings along both sides of the backbone
Each spinal nerve is made up of a group of motor axons, projecting from the ventral (front) part of the spinal cord to the organs and muscles, and a group of sensory axons that enter the dorsal (rear) part of the spinal cord.
What are the 31 spinal nerve segments?
8 cervical (neck)
12 thoracic (torso)
5 lumbar (lower back)
5 sacral (pelvic)
1 coccygeal (bottom)
What are the divisions of the autonomic nervous system?
SYMPATHETIC NS: fight or flight
PARASYMPATHETIC: rest & digest
The sympathetic and parasympathetic systems have very different effects on individual organs because the organs receive different neurotransmitters from the two opposing systems (norepinephrine from sympathetic nerves and acetylcholine from parasympathetic nerves; see Chapter 2 and Figure 11.19). The balance between the two systems determines the state of the internal organs at any given moment. So, for example, when parasympathetic activity predominates, heart rate slows, blood pressure drops, and digestive processes are activated. As the brain causes the balance of autonomic activity to become predominantly sympathetic, opposite effects are seen: increased heart rate and blood pressure, inhibited digestion, and so on. This tension between parasympathetic and sympathetic activity ensures that the individual is appropriately prepared for current circumstances.
How does the sympathetic nervous system work?
Axons exit from the middle parts of the spinal cord, travel a short distance, and then supply the SYMPATHETIC GANGLIA (small clusters of neurons found outside the CNS), which run in two chains along the spinal column
Axons from the sympathetic ganglia spread throughout the body, supplying all the major organ systems. In general.
How does the parasympathetic nervous system work?
Nerves originate in the brainstem (above the sympathetic nerves) and in the sacral spinal cord (below the sympathetic nerves).
Parasympathetic nerves travel a longer distance before terminating in PARASYMPATHETIC GANGLIA, clusters of neurons that are usually located close to the organs they serve.
What are the anatomical conventions for describing the anatomy of the brain?
SAGITTAL PLANE: The plane that divides the body or brain into right and left portions.
CORONAL PLANE (also frontal plane/transverse plane): The plane that divides the body or brain into anterior and posterior parts.
HORIZONTAL PLANE: The plane that divides the body or brain into upper and lower parts.
What is the anatomical meaning of BASAL?
“towards the bottom”
What are afferent and efferent nerves?
AFFERENT: Sensory nerves. Carries information to the CNS.
EFFERENT: Motor nerves. Carries info away from CNS to muscles.
What is the cerebral cortex?
The outer covering of the cerebral hemispheres, which consists largely of nerve cell bodies and their branches.
What are grey matter and white matter and what do they do with info?
GREY MATTER: Areas of the brain that are dominated by cell bodies and are devoid of myelin. Mostly receives and processes information.
WHITE MATTER: Layer of tissue, consisting mostly of myelin-sheathed axons, underneath gray matter. Mostly transmits information.
What is on the cortical surface?
Gyri (gyrus): ridges of tissue
Sulci: Crevices separating gyri
What are the four major cortical REGIONS of each cerebral hemisphere?
The frontal, parietal, temporal, and occipital lobes
What is the Sylvian Fissure and Central Sulcus?
Sylvian fissure: divides the temporal lobe from other regions of the hemisphere.
Central sulcus: fissure dividing the frontal and parietal lobes.
What general function is the frontal lobe associated with?
What is the function of the precentral gyrus and where is it located?
- Frontal lobe: movement planning and high-level cognition.
- Precentral gyrus is crucial for motor control and is referred to as the primary motor cortex. Located in the frontal lobe, anterior of the central sulcus.
What general function is the parietal lobe associated with?
What is the function of the postcentral gyrus and where is it located?
- Parietal lobe receives sensory info and participates in spatial cognition.
- postcentral gyrus mediates the sense of touch and is referred to as the primary somatosensory cortex. Located in the parietal lobe, posterior to the central sulcus.
What does “somatotopic organization” mean?
the precise mapping of various parts of the contralateral body on the cortex.
What does “contralateral side of the body” refer to?
The side of the body opposite to a given brain hemisphere
What is the neural tube?
An embryonic structure with subdivisions that correspond to the future brain and spinal cord.
What is the forebrain DIVISION of the brain?
The front division of the neural tube and brain.
- Contains the cerebral hemispheres, the thalamus, and the hypothalamus.
What is the telencephalon?
The anterior part of the fetal forebrain, which will become the cerebral hemispheres in the adult brain after 50 days.
