Anatomical Directions
Imagine that you are a four-legged creature
Anterior: towards the head
- Also known as rostral
Posterior: towards the tail
- Also known as caudal
Ventral: belly side of the body
- Also known as inferior
Dorsal: towards the back side of the body or the top of the head
- Also known as superior
Lateral: towards the outside of the body
Medial: towards the middle of the body
Brain Locations
Ipsilateral: on the same side of the brain
Contralateral: on different sides of the brain
Planes of the Brain
Sagittal plane: cuts the brain so we see the left/right sides of the brain
Coronal plane: cuts the brain so we see the front/back sides of the brain
Horizontal plane: cuts the brain so we see the top/bottom sides of the brain
Brain Imaging
CT Scan:
MRI:
PET Scan: uses a tracer to see where glucose is being most used at the moment (this
shows what part of the brain is currently active)
Nervous System
Central Nervous System: contains the brain and the spinal cord
Brain Subdivisions:
Hindbrain: very simple brain function (ie breathing, heart rate, muscle
tone)
-
Myelencephalon
a. Structures it contains:
1. Medulla oblongata
I. controls heart breathing and muscle tone
- Metencephalon
a. Structures it contains:
1. Pons
I. Controls sleep and arousal
II.
Where Ach comes from
III. Contains the Locus Coeruleus
- Where Norepinephrine comes from
IV.
2. Cerebellum
I. “Little brain”
II.
Important for motor control
- Important for fine motor control and
balance
III.
- Reticular formation runs through the hind and midbrain
Midbrain = mesencephalon
a. Visible Structures it contains
1. Tectum
I. Location: at the dorsal part of the midbrain
II.
Made up of two “lumps”
- Superior colliculi: involves visual systems
a. Involved in object avoidance
1. Not a conscious process of
seeing
- Inferior colliculi: involves auditory systems
a.
III.
2. Pineal Gland
I. Location: above the tectum
II.
Function: important for circadian rhythms
3.
b. Internal structures it contains:
1. Tegmentum
I. Location: under the tectum (ventral to the tectum).
If you slice the tectum away then underneath it you
will find the tegmentum
II.
Made up of:
- Periaqueductal grey
a. Function: pain regulation
- Red nucleus
a. Function: motor system
- Substantial nigra (the black structure in the
image above)
a. Function: motor system
b. Where dopamine comes from
- Reticular formation (only the rostral end of
the structure)
a. Part of the reticular formation runs
through the hindbrain as well
b. Function: regulates
sleep/wakefulness, helps with muscle
reflexes, breathing, and pain
perceptions
c. Contains the raphe nucleus
1. Where serotonin comes from
d.
III.
2.
c.
Forebrain: more “human”/complicated traits
- diencephalon:
a. Location: on top of the midbrain
b. Not visible on the outside
c. Structure it contains:
1. Thalmus
I. Function: where senses synapse
- Each sense goes to a specific part of
the thalamus
- Smells is a sense that does not
synapse here
II.
2. Hypothalamus
I. Function: controls/regulates the autonomic
nervous system
II.
3.
-
d.
telencephalon:
a. Outer cortex of the brain that we usually picture when we
imagine a brain
b. Structures it contains:
1. Basal ganglia
I. Looks like a ram's horn
II.
Function: movement control, proprioception
- Controls more slow, smooth
movments
III. Structure:
- Globus pallidus: the “core”
- Putamen + Caudate nucleus =
striatum
a. The outer part of the basal
ganglia
IV.
V.
2.
c.
Peripheral Nervous System
Somatic Nervous System: nerves that connect the sensory receptors and voluntary
skeletal muscles
- We have conscious control of this system
Automatic Nervous System: nerves that connect the heart, blood vessels, smooth
muscles, and glands
Sympathetic Nervous System
Parasympathetic Nervous System
Other Brain Structure
Meninges: the layers of membranes that protect the brain and spinal cord
Layers (from outer to inner layer):
- Dura mater
a. A very thick layer
- Arachnoid layer
a. Has finger-like projections that look like spider legs
b. Between arachnoid and pia matter, there is a space of cerebral
spinal fluid
1. The cerebral spinal fluid flows into this space from the
fourth ventricle
- Pia mater
a. Thin layer
Cerebral Spinal Fluid (CSF)
Function: protect the brain from shock
Locations:
- Between the arachnoid layer and the pia mater layer
- Inside the brain ventricles
- Produced by choroid plexus
- Hydrocephalus: a congenital or acquired condition where there is too much CSF in the
brain
1. This increases the size of the ventricles of the brain which could damage the
surrounding brain tissue
2. Can be caused by injury, disease, or present during or shortly after birth
Ventricles
- Good points to inject drugs when we need them to pass the blood-brain barriar
- The ventricles increase in size with the death of brain tissue
Locations:
- There are four of them
a. Lateral ventricles x2
1. The two big ones that look like “rams horns”
b. Third ventricle
1. CSF flows from the lateral ventricles, through the
interventricular foramen, and into the third ventricle
c. Fourth ventricle
1. CSF flows from third ventricle, through the cerebral
aqueduct, and into the fourth ventricle
How Motor Movement Happens
GPe = Globus pallidus external
GPi = Globus pallidus internal
STN = Subthalamic nuclei
SN = Substantia nigra