Biology & Behavior Chapter 2

Section 1: The Nervous System

It’s almost like running is this great friend we both share…Anyway, that’s what I’d like to talk to you about… running as a friend, as a companion, a lover even…in other words, the relationship of running. “WHAT!?” many of you will be saying. “I thought that I was going to learn how to improve my 10k time.” GO read Runner’s World for that. You see, I don’t view running as what I DO or who I AM, but as this thing, this force, that changes me over time. From “Running and Me: A love Story” by Joan Nesbit, 1999

Neurons Nerve cells that run through our entire body and communicate with one another 100 billion neurons, most found in brain

The Nervous System Central Nervous System Peripheral Nervous System Brain & Spinal Cord Nerve cells that send messages between the central nervous system and all parts of the body

Parts of a Neuron Cell body – produces energy that fuels the activity of the cell Dendrites –receive information from other neurons and pass the message through the cell body Axons –carries messages away from cell body

Myelin – white fatty substance that insulates and protects the axon; also speeds up transmission of messages Axon terminals – small fibers at the end of the axon

The Communication Process Messages sent from the axon terminals of one neuron to dendrites of other neurons Crosses synapse (junction between the axon terminals of one neuron and the dendrites of another neuron) Messages travel in only one direction

Neurotransmitters: Chemical Messengers Neurotransmitters (the message)are chemicals that are stored in axon terminals Neurons can fire hundreds of times every second Several types of neurotransmitters, each with their own structure

The Central Nervous System Transmits messages between the brain and the muscles and glands throughout the body Also involved in spinal reflexes

The Peripheral Nervous System Made up of the Somatic Nervous System & the Autonomic Nervous System

The Somatic Nervous System AKA the skeletal nervous system Transmits sensory messages to the CNS Activated by touch, pain, changes in temperature, changes in body position Enables us to experience hot and cold and to feel pain and pressure Helps us maintain posture and balance

The Autonomic Nervous System Regulates body’s vital functions (heartbeat, breathing, digestion, blood pressure) Don’t have to think about these activities...happen automatically Made up of the Sympathetic & Parasympathetic nervous systems

Sympathetic Nervous System Prepares body for action To either run away or confront situation “Fight or Flight” response Suppresses digestion, increases heart & respiration rates, elevates blood pressure

Parasympathetic Nervous System Restores the body’s reserves of energy after an action has occurred Heart rate & blood pressure are normalized, breathing slowed, digestion returns to normal

CNS PNS Nervous System Spinal Cord Brain Autonomic System (involuntary muscles & internal organs) Parasympathetic System (Calms body after emergencies Sympathetic System Prepares body for action Somatic System (voluntary muscles & sense organs)

For homework: On a half sheet of paper… explain how a neuron works using the metaphor of a relay race. Be sure to be specific and detailed in your description.

Section 2: The Brain

The Brain Mind, or consciousness, dwells within the brain Divided into 3 sections Hindbrain Midbrain Forebrain http://www.youtube.com/watch?v=VF5PyeMG8Lo&safety_mode=true&persist_safety_mode=1&safe=active

Hindbrain Medulla oblangata – Involved in vital functions (heart rate, blood pressure, and breathing) Pons –regulates body movement, attention, sleep, and alertness Cerebellum – “little brain” – balance and coordination

Midbrain Vision & hearing Contains part of reticular activating system Important for attention, sleep, and arousal Increases heart rate & blood pressure

Forebrain Four major areas Thalamus Hypothalamus Limbic System Cerebrum

Thalamus A relay station for sensory stimulation

Hypothalamus Regulates body temperature, storage of nutrients, & various aspects of motivation & emotion Involved in hunger, thirst, sexual behavior, caring for offspring, & aggression Disturbances within the hypothalamus can lead to unusual drinking & eating behaviors

Limbic System Involved in learning and memory, emotion, hunger, sex, and aggression If damaged, people can recall old memories but not create new ones

Cerebrum Surface of cerebrum known as the cerebral cortex (outer layer of brain) Part that makes us uniquely human – the part that thinks Also deals with memory, language, emotions, complex motor functions, perception

Cerebral Cortex Divided into two hemispheres Corpus Callosum connects two hemispheres Information received by one side of the body is transmitted to the opposite hemisphere Each hemisphere is divided into four lobes Frontal Lobe Parietal Lobe Temporal Lobe Occipital Lobe

Senses and Motor Behavior Occipital lobe contains primary visual area Damage creates unusual conditions: may be able to recognize an object but unable to differentiate it from another similar object Temporal lobe contains hearing or auditory area If damaged a person may not be able to recognize common sounds

Parietal lobe – receives messages from skin senses (warmth, touch, cold, pain) Frontal lobe – home to the motor cortex (neurons fire when we move certain parts of our body)

Association Areas Shape information into something meaningful Frontal lobe association areas where we solve problems, make plans and decisions

Left vs. Right Hemispheres Left Hemisphere Right Hemisphere Language functions, logic, problem-solving, math imagination, art, feelings, spatial relations For nearly all right-handed people, language functions are based in left hemisphere Language functions also based in left hemisphere for 2/3rds of left-handed people Although differences exist between two hemispheres, they don’t act independently of each other

How do we study the brain? Accidents Electrical Stimulation of the Brain – shows that specific areas are associated with specific types of sensations EEG – device that records electrical activity in the brain Scans MRI – lie in a magnetic field – brain gives off extra energy from radio waves and creates visual images Good for small injuries CAT – X-ray beams passed through head and form 3-d images of brain fMRI – fast kind of MRI that shows the brain at work PET – radioactive sugar injected into body – as it reaches the brain – more is used in areas of greater activity – images show this activity

Section 3: The Endocrine System

The Endocrine System Glands that secrete hormones into the bloodstream Pituitary Gland – The “master gland” Secretes growth hormone, hormone to stimulate labor in pregnant women Thyroid Gland – controls metabolism Pineal Gland – produces melatonin & affects sexual development Adrenal Gland – produce adrenaline & nonadrenaline Testes & Ovaries – produce testosterone, estrogen, progesterone

Section 4: Heredity

Heredity Transmission of characteristics from parents to offspring Genes – basic building blocks of heredity 46 chromosomes divided into 23 pairs 23rd chromosome – boys xy and girls xx Dad determines sex of offspring

Nature-Nurture Debate What people inherit Inherited characteristics determine the kind of people we are Nurture Environmental factors Family, education, culture, living conditions, everyday experiences Today, most psychologists believe both are involved

Kinship Studies Common way to study nature vs. nurture Twin studies – to determine which traits are genetically inherited Adoption studies – do kids act more like biological or adopted parents? Twins reared apart – still share many traits