Nervous System Organisation Flashcards
The vertebrate nervous system =
CNS + PNS
What does the CNS consist of?
Consists of the brain (ventricles) + spinal cord (narrow central canal)
- Derived from (during development) → Dorsal embryonic nerve cord
- Hollow → phylogenetic feature of chordates
_____ = command centre of the body
____ ______ = enclosed and protected in vertebrae
Composition of the brain: water (78%) fat (10%) protein (8%)
Brain
Spinal cord
Grey matter:
White matter:
Neuron cell bodies
Bundled axons.
Brain = has ____ over White
Spinal Cord = has White over _____.
Grey
Grey
In the spinal cord, white matter on the outside shows its role in linking ____ to ___. In the brain, white matter is on the inside and plays a role in signalling between neurons for learning, emotions, senses etc.
CNS
PNS
Brain Layers
Function:
PROTECTION
Bone =
skull
3 layers of connective tissues →
→ meninges
- Dura mater (outer)
- Arachnoid (middle)
- Pia mater (inner)
What is CSF (Liquor cerebrospinalis)? (4)
- in subarachnoid space between arachnoid and pia mater
- physical barrier – cushioning effect
- chemical barrier – isolates from infection
- secreted from specialised capillaries into ventricles
What are the three major anatomical and functional divisions of the brain?
What are the four functional lobes?
Lateralization:
During brain development after birth – competing functions segregate and displace each other into left and right hemispheres.
What are the functions of the right and left hemispheres of the brain?
What is the function of the PNS? (2)
- Transmits information to and from CNS
- Regulates vertebrate movement and internal environment → connected to the entire body
- Sensory neurons :
- Motor neurons :
- running from stimulus receptors that inform the CNS of
the stimuli - running from the CNS to the muscles and glands - called
effectors that take action.
Information runs from: (4)
Sensory neurons → CNS → Motor neurons → Effectors
Cranial + Spinal Nerves
Consists of left-right pairs of cranial and spinal nerves and associated glia.
What are the 12 pairs of cranial nerves that connect directly with the brain?
31 pairs of spinal nerves →
____ [involuntary or unconscious] and ____ [relating to body].
autonomic
somatic
The neurons of the motor system carry signals to _____ muscles.
Motor control can be voluntary, or involuntary as in the ____-____ reaction controlled by the spinal cord.
In contrast regulation of ____ and ____ muscles by the autonomic nervous system is generally involuntary. The _____ and ______ divisions of the autonomic nervous system regulate the organs of the digestive, cardiovascular, excretory, and endocrine systems.
skeletal
knee-jerk
smooth
cardiac
sympathetic
parasympathetic
PNS divides into:
somatic nervous system + autonomic nervous system
What are the two functional components of the nervous system?
- Somatic or Motor carries signals to and from skeletal muscles, mainly in response to external stimuli.
- Autonomic regulates the internal environment by controlling smooth and cardiac muscle, and organs of digestive, cardiovascular, excretory, and endocrine systems.
What is the SOMATIC or MOTOR DIVISION? (3)
- Signals to and from skeletal muscles, mainly in response to external stimuli
- Conscious and involuntary control
- Much skeletal muscle actually controlled by reflexes mediated by spinal cord and/or brainstem
What is the AUTONOMIC DIVISION? (2)
- Regulates internal environment – generally involuntary, autonomic
- 2 divisions = parasympathetic, sympathetic, enteric
