1. Chapter 3
Body and mind

2. 3.1 The Nervous System
The Nervous System regulates our internal functions
2 parts:
Central Nervous System—brain and spinal cord
Peripheral Nervous System—nerve cells that send messages between the central nervous system and the body

3. Neurons
Neurons—communicate with each other and structures in the body, such as muscles and glands
Components of a neuron:
Cell body—produces energy that fuels activity
Dendrites—receive information from other neurons and pass them through the cell body
Axon—carries messages away from the cell body
Usually only one axon per neuron
Axon terminals—passes message to next neuron, or structure

5. Communication Process
In order for a message to be sent, it must cross a synapse. A synapse is a junction between the axon terminal of one neuron and the dendrites of another
Messages travel in only one direction
Sensory neurons carry information to the CNS
Motor neurons carry information away from the CNS
New synapes form as we learn something new
Sometimes the messages-sending process can be disrupted

6. Neurotransmitters: Chemical messengers
Neurotransmitters are chemicals that are stored in sacs
The neurotransmitter will leave one axon terminal, cross a synapse, and be received by the dendrite of the next neuron
Neurotransmitters fit into a specific site (lock & key)
Acetylcholine—muscle control (skeletal)
Dopamine—motor behavior
Noradrenaline—preparing the body for action
Serotonin—emotions and sleep

7. Central Nervous System
The central nervous system consists of the brain and the spinal cord
The spinal cord transmits messages between the brain and the muscles and glands throughout the body
Spinal Reflex—simple, automatic response to something
The brain is not involved in this spinal reflex
Example: Doctors check knee-jerk reaction to make sure your neurons are firing the way they are supposed to

8. Peripheral Nervous System
The peripheral nervous system is responsible for transmitting messages between the CNS and all parts of the body
There are 2 parts:
Somatic Nervous System—transmits sensory messages to the CNS
Enables us to experience sensation
Autonomic Nervous System (involuntary)—regulates the body’s vital functions (heartbeat, breathing, digestion, blood pressure)
Sympathetic—activated when a person is going into action
“Fight or Flight Response”
Suppresses unnecessary body functions and heightens others
Suppressed—digestion
Heightened—heart rate and reparations
Parasympathetic—restores the body to normal state
Heart rate, breathing, blood pressure, digestion all return to normal

9. 3.2 The Brain-Our Control Center

10. The Brain
3 Sections
Hindbrain
Midbrain
Forebrain

11. Hindbrain Medulla—regulates heart rate, blood pressure, and breathing
Pons—regulate body movement, attention, sleep, and alertness
Cerebellum—balance and coordination

12. Midbrain Involved in vision and hearing
Also arousal, sleep, and attention

13. Forebrain Thalamus—serves as the relay station for sensory simulation
Hypothalamus—regulates body temperature, stores nutrients, and various aspects of motivation and emotion (hunger, thirst, sexual behavior, caring for offspring, and aggression)
Limbic System—involved in learning and memory, emotion, hunger, sex, and aggression
Cerebrum—concerned with thinking, memory, language, emotions, complex motor function, perception, and much more

14. 3.3 The Endocrine System
The endocrine system consists of glands that secrete substances called hormones
These glands include pituitary gland, thyroid gland adrenal gland, and the testes and ovaries

15. Pituitary Gland
Size of a pea
Secretes the growth hormones

16. Thyroid Gland
The thyroid produces thyroxin which affects the body’s metabolism
Metabolism is the conversion of food into energy
Hypothyroidism leads to weight gain
Hyperthyroidism leads to weight loss

17. Adrenal Gland
Adrenal Gland secretes Cortical Steroids which increase resistance to stress and promote muscle development
They also secrete adrenaline and noradrenaline which enables a person to deal with stress

18. Testes (males) and Ovaries (females)
These glands produce testosterone, estrogen, and progesterone
Testosterone—aids in growth of muscles and bones as well as primary and secondary characteristics
Primary characteristics—reproduction
Secondary characteristics—distinguishing characteristics between males and females
Estrogen—female sex hormone and fosters primary and secondary characteristics
Progestogen—helps regulate the menstrual cycle

19. 3.4 Heredity-Our Genetic Background
Heredity is the transmission of characteristics from parents to offspring
Includes:
Physical traits—height, hair, eye color
Psychological traits—shyness, leadership, and aggressiveness
Environment can also play a role in shaping these traits
Psychological disorders may also be passed down through heredity (anxiety, depression, schizophrenia)

20. Genes and Chromosomes Genes are the basic building blocks of heredity
Traits are determined by pairs genes—one from each parent (eye color or blood type)
Genes are found in threadlike structures called chromosomes
46 or 23 pair in each cell
22 are similar for males and females, the 23 pair determines sex (male or female)
Males—XY, Females—XX
When a child is born without 46 chromosomes, physical and behavioral disorders may result

21. Nature vs Nurture
Nature refers to what people inherit biologically from their parents
Nurture refers to environmental factors, or what a person is exposed to in life (family, education, culture, living conditions)