Biology 201 Study Guide

Only available on StudyMode
  • Download(s) : 180
  • Published : April 24, 2013
Open Document
Text Preview
BIO 201 – HUMAN ANATOMY AND PHYSIOLOGY I
CHAPTER 13: THE BRAIN AND CRANIAL NERVES- CLASS LECTURE NOTES VISUAL A & P,MARTINI

SECTION 1: FUNCTIONAL ANATOMY OF BRAIN AND CRANIAL NERVES

INTRODUCTION: Brain characteristics
A. Equals ~97% of body’s neural tissue in adults
B. “Typical” brain
1. Weighs 1.4 kg (3 lb)
2. Volume of 1200 mL (71 in.3)
C. Size varies among individuals
1. Male brains are ~10% larger than female (related to body size) 2. No correlation between size and intelligence
3. Normal function occurs from smallest (750 mL) to
largest (2100 mL) brains

EMBRYONIC BRAIN DEVELOPMENT AT 4 WEEKS
A. Neural tube is present: A hollow cylinder that is the beginning of CNS B. Has internal passageway (neurocoel)
C. Cephalic portion enlarges into three portions (primary brain vesicles) 1. Prosencephalon (proso, forward + encephalos, brain)
“FOREBRAIN” is at tip of neural tube
2. Mesencephalon
“MIDBRAIN” is an expansion caudal to prosencephalon
3. Rhombencephalon
“HINDBRAIN” caudal portion, continuous with spinal cord

EMBRYONIC BRAIN DEVELOPMENT AT 5 WEEKS
(secondary brain vesicles develop)
1. Prosencephalon
a. Diencephalon (dia, through + encephalos, brain)
* Becomes THALAMUS, a major relay center
b. Telencephalon (telos, end)
* Becomes CEREBRUM in adult brain
2. Rhombencephalon
a. Metencephalon (meta, after)
* Adjacent to mesencephalon
* Forms CEREBELLUM and PONS in adult brain
b. Myelencephalon (myelon, spinal cord)
* Becomes medulla oblongata in adult brain

MODULE 13.1 MAJOR BRAIN REGIONS
1. CEREBRUM
a. Divided into a pair of large cerebral hemispheres
b. Outer surface is a layer of gray matter = Cerebral cortex (cortex, rind or bark) c. Superficial cerebral structures
1) Fissures - Deep grooves that subdivide hemispheres
2) Gyri (singular, gyrus) - Folds in cerebral cortex that increase surface area (also called convolutions) 3) Sulci (singular, sulcus) - Shallow depressions in cerebral cortex that separate adjacent gyri d. Functions

1) Conscious thought
2) Memory storage and processing
3) Regulation of skeletal muscle contractions
2. CEREBELLUM
1) Partially hidden by cerebral hemispheres
2) Second largest structure of brain
3) Function - Coordination and modulation of motor commands from cerebral cortex

3. Diencephalon - Two parts
a. THALAMUS - Sensory relay and processing center
b. HYPOTHALAMUS (hypo-, below)
* Floor of diencephalon
* Contains centers involved with
1) Emotions
2) Autonomic function
3) Hormone production
4. Brain stem - 3 parts
a. MIDBRAIN
* Contains nuclei that coordinate visual and auditory reflexes * Contains centers that help to maintain consciousness
b. PONS (pons, bridge)
* Connects cerebellum to brain stem
* Has tracts and relay centers
* Contains nuclei that function in somatic and visceral motor control 5. MEDULLA OBLONGATA
a. Relays sensory information to other areas of brain stem and thalamus b. Contains 3 major vital reflex centers
1) heart rate
2) blood pressure
3) blood vessel diameters
6. Ventricles of the brain
a. Fluid-filled cavities
b. Filled with cerebrospinal fluid
c. Lined with ependymal cells
d. Connected by narrow canals
e. Four ventricles
1) 1 & 2. Lateral ventricles
* Contained within each cerebral hemisphere
2) Third ventricle
* Contained within diencephalon
* Connected to fourth ventricle by aqueduct of the midbrain

3) Fourth ventricle
* Begins in metencephalon and extends into superior portion of medulla oblongata * Then narrows to become central canal of spinal cord

MODULE 13.2: CRANIAL MENINGES AND CEREBROSPINAL FLUID

A. Cranial meninges (membranes that...
tracking img