Lecture 19 Flashcards
What makes up the peripheral nervous system?
Neurons outside the CNS
What is the CNS (central nervous system)?
the brain and spinal cord
Where are most neurons located?
in the CNS
What does the PNS comprise?
the somatic nervous system, for controlling voluntary action via skeletal muscle, and the autonomic nervous system, for visceral functions such as heart rate and breathing.
Somatic nervous system
a component of the peripheral nervous system associated with the voluntary control of the body movements via the use of skeletal muscles.
Autonomic nervous system
a component of the peripheral nervous system that regulates involuntary physiologic processes including heart rate, blood pressure, respiration, digestion, and sexual arousal.
enteric nervous system
controls digestion and movements of the gut. It gets input from spinal cord, but can also work independently.
What are glia cells?
non-neuronal cells (i.e. not nerves) of the brain and nervous system
- support and protect neurons, and are about as numerous.
Where are white and grey matter?
in the CNS
Grey Matter
nerve cell bodies, unmyelinated axons, and dendrites.
Role of grey matter
that plays a crucial role in allowing you to function normally day to day. It consists of high concentrations of neuronal bodies, axon terminals (endings) and dendrites.
White matter
consists of myelinated axons running in bundles called tracts.
Role of white matter
allows the exchange of information and communication between different areas of your brain.
Ganglia
groups of nerves or brain cells that are closely related
Ganglion
a collection of neuronal bodies found in the voluntary and autonomic branches of the peripheral nervous system (PNS)
The brain has just ____ of the body’s mass, but gets ____ of the blood pumped by the heart.
~2%
15%
What consumes half the body’s glucose?
The CNS
The spinal cord has ____ segments, each with a pair of spinal nerves
31
What are the four roots each spinal cord segment has?
an anterior (ventral) and posterior (dorsal) root on both right and left sides
dorsal root
which carries afferent (i.e. incoming, sensory) signals.
ventral root
carries efferent (i.e. outgoing) signals from the CNS to the body, including motor signals (i.e. to skeletal muscles).
The dorsal root ganglion
contains the cell bodies of the neurons carrying these signals.
‘Dorsal’ means…
toward the back
‘ventral’ means…
toward the belly
Where is grey matter mainly located in the spinal cord?
in the middle of the cord
How does the CNS save energy?
by limiting communication between neurons
At any moment, only ___ of your neurons are firing.
~4%
The spinal nerve has a _______ shape with a _____ and a ______ horn on each side
butterfly
dorsal
ventral
Spinal reflex
simple behaviours produced by central nervous system (CNS) pathways that lie entirely within the spinal cord
** without consulting the brain
What nuclei does grey matter consist of?
sensory and motor nuclei
Somatic sensory nuclei get signals from….
skin
visceral sensory nuclei get signals from the…
viscera (internal organs)
Efferent nuclei are _____
ventral
Autonomic efferent nuclei send ….
commands to glands and smooth muscle
motor nuclei send….
commands to skeletal muscle
Ascending tracts
carry sensory signals to the brain. They are mainly dorsal because sensory signals arrive at the dorsal horn.
Descending tracts
carry signals from the brain. They are mainly ventral, where outgoing signals leave the CNS.
Propriospinal tracts
communicate information over short and long distances in the spinal cord
6 major divisions of the brain
- Cerebrum
- Pons
- Medulla
- Cerebellum
- Diencephalon
- Midbrain
What make up the rain stem?
medulla, pons and midbrain
What is the brainstem?
the main control center for many autonomic functions and reflexes, such as breathing, swallowing, vomiting, and regulating blood pressure.
What are cranial nerves?
nerves that are ones that enter or leave the brain rather than the spinal cord
Roles of cranial nerves
can play a role in sensation, movement or both.
What does the diencephalon consist of?
the thalamus, hypothalamus, pituitary and pineal
What is the role of the thalamus?
to process information going to and from the cerebral cortex.
What is the role of the hypothalamus?
regulation of behavioural drives, endocrine and autonomic homeostasis
What connects the 2 hemispheres of the cerebrum?
the corpus callosum
What glands secrete hormones in the CNS?
Pituitary and pineal glands
Cerebral lateralization
functional specialization of the two cerebral hemispheres.
What makes up the corpus callosum
a large bundle of myelinated axons.
4 Lobes of each brain hemisphere
Frontal
Parietal
Occipital
Temporal
limbic system
the part of the brain involved in our behavioural and emotional responses, especially when it comes to behaviours we need for survival: feeding, reproduction and caring for our young, and fight or flight responses.
Cingulate gyrus (part of the limbic system)
is an arch-shaped convolution situated just above the corpus callosum and has an important part of the limbic system, the cingulate gyrus helps regulate emotions and pain
What brain parts consist of the limbic system?
the cingulate gyrus, amygdala, and hippocampus.
What is the role of the basal ganglia?
responsible primarily for motor control, as well as other roles such as motor learning, executive functions and behaviors, and emotions.
