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74 Cards in this Set
- Front
- Back
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Draw the map of the nervous system
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:)
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CNS
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Brain
Spinal cord |
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PNS
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Somatic system
- Spinal nerves Visceral system -AKA autonomic nervous system -Contains parasympathetic and sympathetic |
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Dorsal
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Top view of brain
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Ventral
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Bottom view of brain
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Lateral
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Side view of brain
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Medial
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Splitting in two
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Anterior
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Rostral
Ahead or front |
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Posterior
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Caudal
Behind or towards the back |
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Dorsal
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Back
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Midline
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Central axis
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Medial
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Midline or towards the middle
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Lateral
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Towards the side
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Ipsilateral
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Same side
Left hand and left leg |
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Contralateral
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Opposite side
Left hand and right leg |
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Parts of the CNS
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Cerebrum, cerebellum, brain stem, spinal cord
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Cerebrum
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Two cerebral hemispheres divided by the sagittal fissure
Contralateral sensation and movement |
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Cerebellum
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Two hemispheres
Ipsilateral motor control |
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Brain Stem
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The most primitive part of the brain
Concerned with life functions |
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Spinal Cord
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Conduit for info to and from the brain
Sensory and motor losses if damaged |
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What brain sections are in the forebrain?
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AKA PROSENCEPHALON
Telencephalon: cerebral cortex Diancephalon: thalamus Retina |
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What brain sections are in the midbrain?
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AKA MESENCEPHALON
Tectum: superior and inferior colliculus Tegmentum |
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What brain sections are in the hindbrain?
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AKA RHOMBENCEPHALON
Metencephalon: cerebellum and pons Myelencephalon: medulla |
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Describe the spinal cord
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The spinal cord has 31 segments
Each segment has a pair of spinal nerves (one left, one right = 62 all together) Each spinal nerve has: 1) A dorsal root for sensory - receives info from PNS 2) A ventral root for motor |
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Name the five regions of the spine and the number of spinal segments in each region
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Cervical - 8
Thoracic - 12 Lumbar - 5 Sacral - 5 Coccygeal - 1 |
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Diagram of spinal cord segment
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:)
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Is the spinal cord of uniform diameter?
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No!
Swelling because of arms and legs |
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Spinal Cord Segmentation
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Spinal cord recieves sensory input from a particular region of the body and supplies motor input to a similar region
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Dermatome
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The sensory region on the skin surface
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PNS
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Somatic System - the voluntary system
-Spinal nerves Dorsal root ganglia Visceral System - ANS -The involuntary system -Pupil constriction, blood pressure, sweating, crying, salvation, GI tract paristalsis, etc |
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Afferent Signals
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Carry information to a place
Usually brings sensory information to the CNS |
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Efferent Signals
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Carry information from a place
Usually refers to taking motor information from the CNS, to a target motor |
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The Meninges
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Meninges means "covering" in greek
Three meninges cover the brain 1) Dura mater: "hard mother", thick like leather 2) Arachnoid: "spider" 3) Pia Mater: "gentle mother" |
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Subarachnoid Space
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Between the arachnoid and pia matter
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The Ventricular System
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A series of ventricles and canals that move CSF within the brain and transport it out to the subarachnoid space
Contains 150mL of CSF You produce 500mL of CSF/day |
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What is CSF
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Produced by choroid plexus
Circulation and protection for brain and spine |
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Ventricles
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Spaces within the brain that contain CSF
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Specificity Coding
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The representing of a specific stimulus by the firing of neurons that are specialized to respond to just one stimulus
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Distributed Coding
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A specific stimulis is represented by a code that is distributed across a population of neurons
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Describe the somatosensory system
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1) Cutaneous: sense of skin
2) Proprioception: sense of limb position 3) Kinesthesis: sense of limb movement |
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How is the somatosensory system unique?
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Receptors are not concentrated in one location, like in the retina or cochlea
They are distributed over a large area |
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Senses are only concerned about:
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change
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Where do peripheral nerves terminate?
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In the spinal cord (spinal nerves) or brain stem (cranial nerves)
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Glabrous skin
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Hairless
Palm |
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Epidermis vs Dermis
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Epidermis = outer layer
Dermis = inner layer |
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Mechanoreceptors
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Most of the sensory receptors of the somatosensory system
Sensitive to physical distortion of the skin Can be distinguished by their location in the skin and their distinctive structures *Diagram page 70 |
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Merkels Disk
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Disk shaped receptor near the border of the epidermis and dermis
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Meissners Corpuscles
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A stack of flattened cells in the dermis just below the epidermis
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Ruffinis Endings
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Many branched fibers within a cylindrical capsule
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Pacinian Corpuscles
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Largest
A layered, onion like capsule that surrounds a nerve fibre deep in the dermis |
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How do mechanoreceptors differ?
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1. Adaptation rate
2. Receptive field size |
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Adaptation Rate
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All sensory receptors quickly respond to the presence of a stimulus
They then become used to the presence of the stimulus Some receptors rapidly adapt, such as pacinian and meissner Some adapt slowly, such as merkels disks and ruffinis endings *Diagram page 72 |
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Receptive Field Size
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The area of the skin when stimulated influences the firing rate of a given neuron
Small - Merkel and Meissner Large - Ruffini and Pacinian ** Table on page 73 |
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Thermoreceptors
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Respond to specific temperatures and to changes in temperature
Separate receptors for warm and cold Particularly interested in change |
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Tactile Acuity
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Measured on the body by measuring two-point discrimination - the smallest separation between two points on the skin that is perceived as two points rather than one
Regions with high tactile acuity have small receptive fields |
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Somatotopy
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The somatosensory cortex has somatotopy (the map of body wall on the brain)
... Particular regions are over represented in the brain Somatosensory cortex is arranged in columns - all neurons have the same receptive field |
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Cortical Neuron Response
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Receptive fields of cortical neurons are smallest on the fingers and become larger in the hand and forearm
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How do mechanoreceptors differ?
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1. Adaptation rate
2. Receptive field size |
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Receptive Field Size
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Increases as you move up the arm
Across the cortex vertically is the same patch of skin Across the cortex horizontally is a different area of skin |
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Plasticity in the Somatosensory System
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Changes in cortical maps caused by increasing or decreasing stimulation
Plasticity from amputation |
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Adaptation Rate
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All sensory receptors quickly respond to the presence of a stimulus
They then become used to the presence of the stimulus Some receptors rapidly adapt, such as pacinian and meissner Some adapt slowly, such as merkels disks and ruffinis endings *Diagram page 72 |
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Neuroplasticity
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A change in the number of size of connections within the brain region
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Receptive Field Size
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The area of the skin when stimulated influences the firing rate of a given neuron
Small - Merkel and Meissner Large - Ruffini and Pacinian ** Table on page 73 |
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Thermoreceptors
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Respond to specific temperatures and to changes in temperature
Separate receptors for warm and cold Particularly interested in change |
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Tactile Acuity
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Measured on the body by measuring two-point discrimination - the smallest separation between two points on the skin that is perceived as two points rather than one
Regions with high tactile acuity have small receptive fields |
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Somatotopy
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The somatosensory cortex has somatotopy (the map of body wall on the brain)
... Particular regions are over represented in the brain Somatosensory cortex is arranged in columns - all neurons have the same receptive field |
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Cortical Neuron Response
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Receptive fields of cortical neurons are smallest on the fingers and become larger in the hand and forearm
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Receptive Field Size
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Increases as you move up the arm
Across the cortex vertically is the same patch of skin Across the cortex horizontally is a different area of skin |
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Plasticity in the Somatosensory System
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Changes in cortical maps caused by increasing or decreasing stimulation
Plasticity from amputation |
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Neuroplasticity
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A change in the number of size of connections within the brain region
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Nociceptors
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Somatic sensation of pain is received by nociceptors
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Nociception is:
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the sensory process that provides the signals that trigger pain
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Hyperalgesia
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An increased sensitivity to painful stimuli
A decreased pain threshold |
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Analgesia
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An inability to sense pain
The brain cannot feel pain itself, nor does it have pain receptors |
