Problem 1
The Nervous System:
1. Central NS: brain + spinal cord
2. Peripheral NS: outside of the brain and spinal cord
a. Somatic NS: interacts with the environment, voluntary motor skills and
movements
b. Autonomic NS: regulates the body’s internal environment and carry
involuntary movements such as heartbeat etc.
i. Sympathetic nerve: arousing - stimulates, organizes and mobilizes
energy
ii. Parasympathetic nerve: relaxation - acts to conserve energy
Afferent neurons: carries information from senses to the brain (A=admit info)
Efferent neurons: carries information from brain to muscles (E=exit info)
Both somatic and autonomic nervous systems have afferent & efferent neurons
Neurons: nerve cells that transmit messages from one part of the body to another
Structure of neurons: dendrite (receive information), cell body (soma), within cell body
there is the nucleus with genetic information, axon (long passage to carry information),
terminal buttons, myelin sheaths (isolates the axon, fastens the information, gives white
color), nodes of ranvier (parts between myelin sheaths that allow ions in and out of the axon)
Types of Neurons:
1. Sensory neurons: afferent neurons that bring into from sense to the CNS
2. Motor neurons: efferent neurons that bring info from the CNS to organs or muscles
3. Interneurons: connect one neuron to another, they can only be found in the CNS,
there is no or short axons and no myelin sheaths
Classifications of neurons:
1. Unipolar: has one extension
2. Bipolar: has 2 extensions
3. Multipolar: has 2 or more extensions
Glial Cells: work to support neurons and surrounds neurons
Protection of the CNS:
● The brain is protected by the skull and 3 membranes called meninges
1. Dura mater: outer mening (tough mother)
2. Arachnoid membrane
a. Beneath arachnoid membrane is a
space called subarachnoid
space that contains large blood
vessels and cerebrospinal fluid
3. Pia meter: innermost mening
● Cerebrospinal fluid: protects the brain
from damage and fills in the spaces and
, ventricles (lateral & 3rd and 4th ventricles), it also fills in the central canal which is a
channel that runs the length of the spinal cord
● Blood-Brain barrier: passage/barrier to withstand the toxins from entering the brain,
has a special structure of tightly packed cerebral blood vessels
Directions of the nervous system
Dorsal = Superior / Ventral = Inferior / Horizontal plane = transverse / Frontal plane =
Coronal / Sagittal plane = Medial
Ipsilateral: same side of the brain
Contralateral: opposite side of the brain
Divisions of the brain
The neural tube forms the
forebrain, midbrain, hindbrain
and spinal cord when an
embryo is 2-3 weeks.
Hindbrain: Metencephalon + Myelencephalon
Myelencephalon: Medulla. It has a reticular formation. Sends
signals from the brain to the body. It’s located at the brain
stem. Control regulation of cardiovascular system - vital
The Nervous System:
1. Central NS: brain + spinal cord
2. Peripheral NS: outside of the brain and spinal cord
a. Somatic NS: interacts with the environment, voluntary motor skills and
movements
b. Autonomic NS: regulates the body’s internal environment and carry
involuntary movements such as heartbeat etc.
i. Sympathetic nerve: arousing - stimulates, organizes and mobilizes
energy
ii. Parasympathetic nerve: relaxation - acts to conserve energy
Afferent neurons: carries information from senses to the brain (A=admit info)
Efferent neurons: carries information from brain to muscles (E=exit info)
Both somatic and autonomic nervous systems have afferent & efferent neurons
Neurons: nerve cells that transmit messages from one part of the body to another
Structure of neurons: dendrite (receive information), cell body (soma), within cell body
there is the nucleus with genetic information, axon (long passage to carry information),
terminal buttons, myelin sheaths (isolates the axon, fastens the information, gives white
color), nodes of ranvier (parts between myelin sheaths that allow ions in and out of the axon)
Types of Neurons:
1. Sensory neurons: afferent neurons that bring into from sense to the CNS
2. Motor neurons: efferent neurons that bring info from the CNS to organs or muscles
3. Interneurons: connect one neuron to another, they can only be found in the CNS,
there is no or short axons and no myelin sheaths
Classifications of neurons:
1. Unipolar: has one extension
2. Bipolar: has 2 extensions
3. Multipolar: has 2 or more extensions
Glial Cells: work to support neurons and surrounds neurons
Protection of the CNS:
● The brain is protected by the skull and 3 membranes called meninges
1. Dura mater: outer mening (tough mother)
2. Arachnoid membrane
a. Beneath arachnoid membrane is a
space called subarachnoid
space that contains large blood
vessels and cerebrospinal fluid
3. Pia meter: innermost mening
● Cerebrospinal fluid: protects the brain
from damage and fills in the spaces and
, ventricles (lateral & 3rd and 4th ventricles), it also fills in the central canal which is a
channel that runs the length of the spinal cord
● Blood-Brain barrier: passage/barrier to withstand the toxins from entering the brain,
has a special structure of tightly packed cerebral blood vessels
Directions of the nervous system
Dorsal = Superior / Ventral = Inferior / Horizontal plane = transverse / Frontal plane =
Coronal / Sagittal plane = Medial
Ipsilateral: same side of the brain
Contralateral: opposite side of the brain
Divisions of the brain
The neural tube forms the
forebrain, midbrain, hindbrain
and spinal cord when an
embryo is 2-3 weeks.
Hindbrain: Metencephalon + Myelencephalon
Myelencephalon: Medulla. It has a reticular formation. Sends
signals from the brain to the body. It’s located at the brain
stem. Control regulation of cardiovascular system - vital
