The Human Brain

1
The Human Brain

• IB Biology
• Joohee Kim
• Sec. III

2
Structure and Functions of Parts of the Brain

• Cerebral Hemispheres
• Sensory information received from outside world
  is processed
• Controls voluntary movement
• Regulates conscious thought and mental activity

3
Structure and Functions of Parts of the Brain

• Cerebellum
• In charge of balance and coordination
• Receives information from eyes, ears, and
  muscles, and joints about bodys movement and
  position

4
Structure and Functions of Parts of the Brain

• Hypothalamus monitors certain activities and
  controls bodys internal clock

5
Structure and Functions of Parts of the Brain

• Medulla Oblongata most inferior portion
• Functions as a conduction pathway
• Reflex centers for
• Regulating heart rate
• Blood vessel diameter
• Coughing, sneezing
• Breathing
• Swallowing

6
Structure and Functions of Parts of the Brain

• Pituitary Gland secretes hormones regulating
  homeostasis
• Hormones are actually made in the nerve cell
  bodies of hypothalamus

7
Investigating Brain Function

• Animal Experiments including primates, surgical
  procedures
• Parts of skull have to be removed
• Animal must be kept alive
• Effects on animal are observed
• Ethical objections
• Animal suffering and sacrifice

8
Investigating Brain Function

• Lesions damaged parts of the brain
• Accidents, strokes, tumors can damage
• Brain functions are deduced
• Example left cerebral hemisphere cause dysphasia
• - Inability to speak but reading, writing possible

9
Investigating Brain Function

• Functional magnetic resonance imaging
• fMRI technique for determining which parts of
  brain are activated by specific thought processes
• Active parts of brain receive increased blood
  flow
• Experimental subject is placed in scanner
• High-resolution scan of brain is taken

10
The Pupil Reflex and Brain Death

• Pupil Reflex when bright light shines into one
  eye and the pupils of both eyes constrict
• If unconscious patients pupils do not constrict
  when a light is shone into eye, it suggests that
  they have injuries serious enough to have caused
  brain death.