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Sheep Brain Dissection Guide

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Sheep Brain Dissection Guide Good Luck!! Meninges of the Brain Brain is protected by the skull and 3 layers of membranes called meninges Observe Meninges Examine the ... – PowerPoint PPT presentation

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Title: Sheep Brain Dissection Guide


1
Sheep Brain DissectionGuide
Good Luck!!
2
Meninges of the Brain
Brain is protected by the skull and 3 layers of
membranes called meninges

3
Observe Meninges
  • Examine the brain to see if there is a tough
    outer coatThis is the DURA MATER (literally
    means tough mother)
  • Now look for the stringy, web-like ARACHNOID
    MATER (literally means spider mother) beneath and
    stuck to the dura mater. The space under the
    arachnoid, the subarachnoid space, is filled with
    cerebrospinal fluid and contains blood vessels.
  • Look deeper and see an thin transparent membrane
    that follows the contour of the ridges (gyri) and
    valleys (sulci) of the brain. This is the PIA
    MATER ( means tender mother)

4
Questions??
  • What is the function of the meninges?
  • Describe the following meninges
  • Dura mater, Arachnoid mater, and Pia mater
  • What is meningitis?

5
Main Brain Regions
  • Identify the cerebrum, brain stem) and cerebellum
    on your brain
  • Draw picture of sheep brain and label structures

Cerebrum
Cerebellum
Brain stem
6
Questions??
  • Which part of the brain allows for
  • 1) Balance
  • 2) Breathing
  • 3) Hearing and Vision

7
Human vs Sheep
  • Compare the various areas of the sheep brain
    (cerebrum, brain stem, cerebellum) to the human
    brain.
  • 4. How is it the same and How is it different?

Human brain
8
Identify Dorsal Structures
  • With the dorsal side up, identify the cerebral
    hemispheres, gyri, sulci,and longitudinal fissure
    on your sheep brain

9
Questions??
  • What does the longitudinal fissure divide?
  • What is the difference between gyri and sulci?
  • What is the purpose of the gyri and sulci?

10
Lobes of the Cerebrum
  • Find the 4 lobes of the brain-frontal, parietal,
    occipital,
  • and temporal
  • Using pins label each lobe
  • Teacher check

11
Questions????
  • Name the lobe that functions in
  • a) Hearing
  • b) Vision
  • c) Touch
  • d) Movement

12
Corpus Callosum
  • At the longitudinal fissure, gently separate the
    two hemispheres and look down between them for
    the thick band of white fibers. This is the
    corpus callosum
  • What is its function?

13
Identify Ventral Structures
  • Place the sheep brain ventral side up.
  • Identify the olfactory bulb, optic nerve, optic
    chiasm
  • Using pins label each structure.
  • Draw and label the structures in lab writeup

14
Questions??
  • How does the human brains olfactory bulb differ
    from the sheeps?
  • Which is able to smell more odors?
  • Look at the optic chiasma. What happens to the
    optic nerve (vision) at the optic chiasma?
  • Which side of the occipital lobe (right or left)
    sees for the right eye?

15
Brain Stem
  • Look at the three parts of the brain stem-the
    midbrain (cerebral peduncle and mammilary body),
    pons and medulla oblongata
  • Pin and label parts
  • Teacher check

16
Function
  • Mammillary bodies serve as relay stations for
    reflexes related to sense of SMELL
  • Cerebral Peduncle-group of myelinated nerves

17
Questions??
  • Label your diagram with parts of midbrain and
    brain stem
  • What is the function of the medulla oblongata and
    pons?
  • Could you survive without them?
  • Why or Why not?

18
Identify dorsal structures
  • Carefully pull the cerebellum away from the
    cerebrum. Dont break any structures off.
  • Identify the pineal body, superior colliculi, and
    inferior colliculi.

19
Functions-Reflex Centers
  • Inferior Colliculi- movement of head and trunk in
    response to sound stimuli
  • Superior Colliculi-movement of eyes, head and
    neck in response to visual stimuli

20
Pineal Gland
  • Produces the hormone melatonin at night
  • Melatonin is the sleep hormone

21
Questions??
  • What is the function of the Pineal body?

22
Midsagittal Section
  • Obtain a brain the has been cut in half
  • Locate the brain stem parts the medulla
    oblongata, the pons, cerebrum, and cerebellum

23
Cerebellum
  • Look at the cross section of the cerebellum. The
    inner structure is called the arbor vitae (living
    tree).

Why is this a good name for it?
24
Midsagittal Section
  • Locate the corpus callosum, thalamus,lateral
    ventricle, fourth ventricle and cerebral aqueduct

25
Questions
  • What is the function of the ventricles?
  • The cerebral aquaduct allows for the circulation
    of the cerebral spinal fluid through the
    ventricles. What do you think would happen if
    the duct became blocked?
  • How would that affect brain tissue?

26
How does the normal brain compare with the
Alzheimers brain? How would that explain the
memory loss?
27
The End!!
  • Good bye or in sheep language

BAA BAA
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