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Human Anatomy Chapter 13


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What anatomy directional term means "toward the snout"
What anatomy directional term means "toward the tail"
The average adult brain weighs about
3.3 pounds.
The average adult brain has about how many neurons...

Life expectancy?
100 billion

100 years
The average adult brain requires what percentage of the heart's cardiac output?
How have we learnd about brain function?
Examples like Phineus gage... where a loss in an area of the brain changes behavior in a particular way.
Anatomists often classify the brain into four parts. What are they?
1.) Cerebral hemispheres
2.) Diencephalon
3.) Brain stem
4.) Cerebellum
Lateral Ventricles are found in the brain's...

They are filled with
Central cavity of the cerebral hemisphere

Where is the third ventricle found

How is it connected to the first two?
the diencephalon

through the interventricular foramen.
the fourth ventricle is found where?

How is it connected to the third ventricle?

Cerebral aqueduct
All the ventricles of the brain are filled with CSF and lined by what cells?

What kind of cells are these considered? function?
Ependymal cells

CNS glial cells
The cerebral hemisphere is the most _____________ structure.

What kind of functions are carried out in the cerebral hemisphere?

Higher level functions such as memory and reasoning.
The Cerebral hemisphere is the portion of the brain that can be seen. Why is this region called the cortex?
Because the cortex is grey matter (non-myelinated interneurons). The grey-mater shows why the cerebral cortex is able to handle the higher-level functions.
The surface of the cerebral cortex has bumps and grooves what are these called?
Bumps are called gyrus
Grooves are called sulcus
What are the lobes of the CEREBERUM. (5 not 4)
Deep cut between the right and left cerebral hemisphere.
Longitudinal fissure
Divides the temporal lobe from the frontal and parietal lobes.
Lateral Sulcus
Divide the frontal lobe and the parietal lobe
Central Sulcus
seperates the cereberal hemispheres from the cerebellar hemisphere?
transverse cerebral fissure
Trick question: What neurons do you expect in each of the following areas of the cerebral cortex:

-Motor area
-Sensory area
All neurons in the cerebral cortex are Interneurons!

NOT sensory neurons or motor neurons

-controls what
-the projection of axons becomes contralateral. What does this cause?
Precentral gyrus.

less complex movements

Right hemisphere controlling left movements and vice versa.
Premotor cortex

-controls what
just rostral to the primary motor cortex

more complex movements than those controlled by the primary motor cortex
Broca's Area

-controls what
Deeper than the Premotor cortex

Speech production
Primary somatosensory cortex

-controls what
postcentral gyrus. Just rostral to the primary motor cortex.

involved with self-consciousness, SOMATIC SENSES (skin temp, pain, pressure, proprioception)
Wernicke's Area

Understanding speech
Prefrontal cortex

most rostral section of the cerebral hemisphere.

Association area of the brain involved in higher level cognition
the loss or impairment in the ability to comprehend or produce speech.
Frontal lobe
-Voluntary motor control
-Higher intellectual processes
-Verbal communication
Involved in the motor control of speech (producing sound)
Parietal lobe
-Speech and Emotions

-Textures and shapes

Post-central gyrus
Occipital lobe
Temporal lobe
Auditory and Vestibular
Insula lobe
Memory (?)
What kind of functions are considered left brained?
Language abilities, math, and logic.

What kind of functions are considered right brained?
The big picture.

visual-spatial skills, reading facial expressions, intuition, emotion, art, music.
Underneath the gray mater of the cerebral cortex we find the white mater (myelinated). These fibers are broken into three classes. What are they?
1.) Commissural fibers
2.) Association fibers
3.) Projection fibers
fibers that cross hemispheres
Commussural fibers
(f.e: Corpus Callosum)
connect different structures on the same hemisphere (right OR left)
Association fibers
These fibers will cross to the opposite hemisphere (right to left or left to right)
Projection fibers
Basal gaglia

-2 major functions
Deep within the cerebral white matter

Coordinates with the cerebral cortex to CONTROL MOVEMENTS. (start, stop and regulate movements)

Also believed to be able to select what muscles are required for what movements.
Realize that the Basal ganglia is in which of the four main parts of the brain
the Cerebral hemisphere
The diencephalon (2nd of 4 major parts) includes what important structures
Thalamus, Hypothalamus and Epithalamus
Structurally the thalamus makes up...
the outside walls of the third ventricle.
Structurally the hypothalamus makes up the...
the floor of the third ventricle
Structurally the epithalamus makes up the..
the roof of the third ventricle
The thalamus is made up of
gray matter
What is the function of the thalamus?
The thalamus is the relay center for SENSORY INFORMATION.
The thalamus recieves afferent sensory information from all senses. What nuclei recieves information for vision? for audition?
Lateral geniculate nucleus

Medial geniculate nucleus
An important fact about the thalmus.
EVERY part of the brain that communicarttes with the cerebral cortex must relay its signals through a nucleus in the cerebral cortex (The Secretary)
the hypothalamus like the thalamus is made up of
gray matter
What 8 functions are carried out by the hypothalamus. Recall that the hypothalmus controls the primary needs to sustain life.
Controls autonomic nervous system (cardiac muscles, breathing)

Controls Emotions

Controls body temperature

Regulates hunger/thirst drives

Controls motivational behaviors (eating, sex)

Regulation of sleep-wake cycles

Control of the endocrine system (most with pituatary)

Formation of memory (?)
Epithalamus includes what notorius gland
The pineal gland is actually a
hormone secreting organ.
the pineal gland secretes _______. Its function is to ________________.

Control sleep/wake cycles.
Structurally the pituatary "hangs on a stick". What is the stick structure called?
The pituatary gland is broken into two regions the anterior portion called the _______________ and the posterior portion called the __________________.

The adenohypophysis (anterior pituatary) actually does what...
acts as a gland and secretes hormones.
the neurohypophysis portion makes and secretes what two hormones
Oxytocin and ADH (vasopressin)
In the midbrain the 2 structures we are required to know are...
Corpora Quadrifemina

Cerebral peduncles
The corpora quadrifemina has what 2 structures? what are their function?
Superior colliculi- tracking movements of the eye.

Inferior colliculi- auditory reflex

-where is it found
- what strucutre does it form
the cerebellum

the bridge between the left and right cerebellum

relays messages
Medulla oblongata

-controls what
-Injuries to what cervical area.
visceral autonomic center

-controls heart rate, breathing

Injury to the C4 and C5 vertebrae could cause damage to the medulla and can stop respiration.
Cerebellar hemispheres

*Coordinate skeletal muscle contraction

*Fine-tunned moving
What are the three levels of meninges?
Dura matter-most superficial layer it is the hardest and best protects the brain from the outside.

Arachnoid space- in between layers of the meninges. it is filled with many vessels making it look like a web.

Pia matter- the deepest of the meninges. it is not very tough but still protects the brain.
What are septa of the dura matter?
Septa are walls between structures of the brain.
what structures of the brain does the Falx cerebri seperate?
the right and lefft hemispheres of the cerebrum.
what structures of the brain does the Falx cerebelli seperate?
the right and left hemispheres of the cerebellum.
what structures of the brain does the tentorium cerebelli seperate?
the cerebrum and cerebellar

(this structure is more horizontal while the other septa are more vertical)
How long is the spinal cord? How wide is it?
1.5 feet, 1 cm
How many sections are there of the spinal cord? what is their break up? WHAT IS TRICKIEST TO REMEMBER AND MOST LIKELY TO BE ON THE TEST?
31 sections

8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal

*** 8 cervical rather than 7 (recall only 7 cervical vertebrae).
How are their 31 sections of the spine? what structures define a "section"
Where spinal nerves pass the vertebrae. The C1 has 2 because some pass above the C1 and some below. This accounts for the 8th section (and only 7th cervical spine)
Structures of the spine

-thicker portion of the spine where the nerves for the arm pass
-thicker portion of the spine where the nerves for the legs pass
-thinnest section of the spine
-the anchor point
-collection of nerve
cervical enlargement

Lumbar enlargement

Thoracic region

Filum terminale

Cauda equina
Where on a vertebrae is the grey matter found? white?
why the colors?
Gray- is made up of unmyelinated cell bodies at the center of the vertebrae

White- myelinated axons around the gray matter.
White matter axons travel _________________ along the length of the spine.
Up and Down
-What is CSF?
-What is its consistancy?
-where does it run?
-what is its derivative?
-Where is it made?
-what is its purpose?
cerebral spinal fluid

like water

the central canal of the spine and in the skull


choroid plexus

to insulate the brain from any blows and to support the weight of the brain.

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