Ch. 3 The Brain and Nervous System
Section 1 The Nervous System
Nervous system- regulates internal functions
-
constantly at work
involved in thinking, dreaming, feeling, memory,
learning, moving
divided into two main parts: Central Nervous System
(CNS)
•brain and spinal cord
Peripheral Nervous System
(PNS)
• Nerve cells, sends messages between CNS and all parts of the body
Neurons- nerve cells
- send and receive messages
Cell body- produces energy that fuels the activity of the cell
Dendrites- thin fibers that receive info from other neurons and pass the
message through the cell body
Axon- carries messages away
-covered w/ myelin- white fatty substance that insulates and
protects the axon
Axon terminals- small fibers that branch out at the end of the axon
Synapse- junction between axon terminals of one neuron-neuron
CX process
Neurotransmitters- chemicals stored in sacs in axon terminals
•endorphins
• dopamine
CNS
•brain and spinal cord
•column of nerves as thick as your thumb
•protected by bones of the spine
PNS
1. Somatic Nervous System- transmits sensory messages to CNS
- activated by pain, touch, temp. changes, body position
2. Autonomic Nervous System- regulates vital functions: heart rate,
breathing, digestion, blood pressure
a. Sympathetic Nervous System-“flight or fight”
b. Parasympathetic Nervous System- restores body to normal
Section 2 The Brain: Our Control Center
Brain- many parts that work together to organize movements, create
thoughts, form emotions, and produce behaviors
-three main parts: Hindbrain, Midbrain, Forebrain
Hindbrain- lower portion of the brain involved in vital functions
a. Medulla-vital functions: heart rate, breathing, blood pressure
b. Pons- regulates body movement, attention, sleep, alertness
c. Cerebellum-“little brain”, balance and coordination
Midbrain- in middle, vision and hearing
a. Reticular Activating System- sleep, attention, arousal
- affected by alcohol
- responds to loud noises
Forebrain- in front
a. Thalamus- inner chamber, relay station that transmits info
b. Hypothalamus- regulates body temp., storage of nutrients,
aspects of motivation and emotion
Limbic System- learning, memory, emotion, hunger, sex, aggression;
“Primal”
Cerebrum- largest part of the brain
•two sides-Hemispheres-connected by corpus callosum
•left hemi. controls right side of body
•right hemi. controls left side of body
•right brained vs. left brained
• each hemi. divided into 4 parts-Lobes
Lobes:
1.
2.
3.
4.
Frontal lobe-behind forehead, motor cortex, higher level thinking
Parietal lobe- top and rear- skin senses, warmth, cold, touch
Temporal lobe-sides below ears- hearing
Occipital lobe- back of head- vision
Association areas- shape all info into something meaningful on which
we can act
1. Wernicke’s Area- in temporal lobe, puts together sight and
sound
- if damaged-difficulty understanding speech
2. Broca’s area- frontal lobe, controls parts of face used for
speaking
- if damaged-slow speech, simple sentences
Section 3 The Endocrine System
Endocrine system- glands that secrete hormones into the blood stream
Hormones- stimulate growth, affect behavior and emotional reactions
Pituitary gland- “master gland”, growth hormones, muscle, bones, glands
Thyroid gland- responsible for metabolism-regulates weight
Adrenal gland- adrenaline-emergency situations, heighten your senses
Reproductive systems- ovaries and testes
Section 4 Heredity: Our Genetic Background
Heredity- transmission of characteristics from parent to offspring
What can we inherit?
Genes- basic building blocks of heredity
-pairs of genes that determine traits
- threadlike structures-chromosomes
Nature vs. Nurture
Nature= what we inherit
Nurture= environmental factors, culture, education, experiences
Kinship studies
Twin Studies- identical or fraternal