3. The Brain
• The Human brain is composed of many
parts that work together to organize our
movements, create our thoughts, form
our emotions, and produce our
behaviors.
• The brain is able to function effectively
because of the intricate system of
support and protection it receives from
other parts of the body.
4.
5. THE BRAIN
• Brain is supported by the nutrients and oxygen
carried by blood vessels and protected by the
bones of the skull and three layers of
membranes.
• Fluid surrounding brain acts as a shock
absorber.
• Divided into three sections: the hindbrain,
the midbrain, and the forebrain.
6. The Brain: Our Control Center
•
The Forebrain - located in the front of the head
• Thalamus relay station for sensory
stimulation
• Hypothalamus regulates body temperature,
the storage of nutrients, hunger, thirst, and
movement
• Limbic System controls learning, memory,
emotion, hunger, sex and aggression
• Cerebrum largest part of the brain about 70%
of weight.
• Surface is wrinkled with ridges and valleys
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8. The Brain: Our Control Center
• The Hindbrain - located at the base of the skull
• Medulla controls vital functions such as heart
rate, blood pressure, and breathing
• Pons regulates bodily movement, attention,
sleep and alertness.
• Cerebellum controls balance and coordination.
• The Midbrain - between the hindbrain and
forebrain
• Reticular Activating System (RAS) controls
vision and hearing.
• Makes people alert
• alcohol reduce the activity of RAS
• screen out certain noises
9. Our Control Center continues…
• Cerebral Cortex outer layer of the brain
• where thinking takes place
• makes us unique
• concerned with memory, language,
emotions, complex motor function and
perception
• Corpus Callosum connects the two hemisphere
of the brain
• aids in getting information from one side of
the brain to the other
10. Left Verse Right Hemisphere
• Left Hemisphere contains language
function, logic, problem solving, and
mathematical computation.
• Right Hemisphere concerned with
imagination, art, feelings, and spatial
relations.
• Both hemisphere of the brain are involved in
most human activities and abilities.
13. Neurons
• Sensory Neurons - nerve cells that carry
information received by the sense to the central
nervous system.
•
Motor Neurons - are nerve cells that carry
information from the central nervous
system to the muscles and the glands and
influence their functioning.
15. Parts of the Neuron
• The cell body is a relatively large, egg-shaped
structure that provides fuel, manufactures
chemicals, and maintains the entire neuron in
working order.
• Dendrites are branchlike extensions that arise
from the cell body; they receive signals from other
neurons, muscles, or sense organs and pass
these signals to the cell body.
• The axon is a single threadlike structure that
extends from, and carries signals away from, the
cell body to neighboring neurons, organs, or
muscles.
• Axons can be several feet long.
16. Parts of the Neuron contd.
• End Bulbs, which look like tiny bubbles, are
located at the extreme ends of the axon’s
branches. Each end bulb is like a miniature
container that stores chemicals called
neurotransmitters, which communicate with
neighboring cells.
• The synapse is an infinitely small space (20-30
billionths of a meter) that exist between an end
bulb and its adjacent body organ (heart), muscles
(head), or cell body.
• Myelin Sheath – insulates an axon & prevents
inference from electrical signals generated in
adjacent axons.
19. Neurotransmitters
• Neurotransmitters refers to about a dozen different
chemicals that are made by neurons and then
used for communication between neurons during
the performance of mental or physical
activities.
• Excitatory – stimulating the firing of messages
If more exist; messages sent on their way
• Inhibitory – slowing the transmission of neural
messages
• • If more exist; messages slowed or stopped
• Foundation of behaviors and mental processes
• Messages are carried in both directions.
• They are stored in sacs in the axon terminals
20. Neurotransmitters conts.
• Types of neurotransmitters:
• • Acetylcholine: controls muscles, used by the
motor neurons of the spinal cord and stimulates
skeletal muscles
• • Dopamine: controls motor behavior, deficiency
in chemical plays a role in Parkinson disease, &
increase causes schizophrenia.
• • Nor-adrenaline: prepares the body for action
• • Serotonin: controls emotional arousal and sleep
• • Endorphins: decreases the effects of pain during
great bodily stress, such as an accident.
21. Gun Analogy - Neurotransmitters
• Action Potential – neuron fires an impulse
• Firing threshold
• “all or none” – the point at which the gun will
• fire, no matter how slowly the trigger is pulled
• • The neuron fires its electrical signal
• Refractory period – the cell cannot fire again.
• Re-uptake - Any excess neurotransmitters left in
• the synapse is recollected
• Antagonist – drugs used to blocks the action of
• neurotransmitters
• Agonist – drugs used to mimic the action of
• neurotransmitters
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23. The Spinal Cord
• The Spinal Cord extend from the brain down the
back
• Column of nerves about as thick as a thumb
• Protected by the bones of the spine
• Transmits messages between the brain and
the muscles and the glands throughout the
body
• Spinal reflex is a simple, automatic response to
something
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35. Brain Scan
• EEG (Electroencephalogram)
an amplified recording of the waves of electrical
activity that sweep across the brain’s surface
these waves are measured by electrodes placed
on the scalp
36. CT (computed tomography) Scan
•
a series of x-ray photographs taken from different
angles and combined by computer into a
composite representation of a slice through the
body; also called CAT scan
37. MRI (magnetic resonance imaging)
• a technique that uses magnetic fields and radio waves
to produce computer-generated images that distinguish
among different types of soft tissue; allows us to see
structures within the brain
38. PET (positron emission tomography) Scan
• a visual display of brain activity that detects
where a radioactive form of glucose goes while
the brain performs a given task
39. Endocrine System
• Hormones: stimulate growth & certain types of
reactions (emotional & physiological)
• Pituitary Gland: below the hypothalamus, size of a
pea
• Master gland (growth) – regulates the
growth of muscles, bones, glands {prolactin –
milk; oxytocin –labor}
• Thyroid Gland: thyroxin converting food to energy
– (metabolism)
• hypothyroidism – overweight;
• hyperthyroidism – excitability,
• inability to sleep & weight loss
40.
41. Endocrine System
• Adrenal Gland: over kidney; cortex secretes
cortical steroids increase resistance to stress,
promote muscles development; cause liver to
release stored sugar produce
• Adrenaline & noradrenaline; deals with
stress
• Testes/Ovaries: produces testosterone, estrogen &
progesterone
• • Mainly reproductive hormones
