OVERVIEW

NEUROANATOMY

Two Neurons

Neuroanatomy refers to the study of the parts and function of neurons

Dendrites(樹(shù)突) - Rootlike parts of the cell that stretcdh out from the cell body

Cell Body(Soma) - Contains the nucleus and other parts of the cell needed to sustain its life

Axon - Wirelike structure ending in the terminal buttons that extends from the cell body

Myelin Sheath - A fatty covering around the axon of some neurons that speeds neural impulses

Terminal Buttons(End Buttons, Terminal Branches of Axon, and Synaptic knobs) - The branched end of the axon that contains neurotransmitters

Neurotransmitters(神經(jīng)遞質(zhì)) - Chemicals contained in terminal buttons that neurons to communicate

Synapse(突觸) - The space between the terminal buttons of one neuron and the dendrites of the next neuron

How a Neuron "Fires"

和生物課上講的一樣

All-or-none Principle - A neuron either fires completely or it does not fire. It depends on whether the Neurotransmitters are accumulated to threshold.

Neurotransmitters

Some neurotransmitters are Excitatory, meaning that they inhibit the next cell from firing. Other neurotransmitters are Inhibitory, meaning that they inhibit the next cell from firing

Memorize this piece of ****

NERVOUS SYSTEM

Afferent Neurons (or Sensory Neurons) - Neurons that take information from the senses to the brain

Interneurons - Neurons that pass information from Afferent Neurons to elsewhere in the brain or on to Efferent Neurons

Efferent Neurons (or Motor Neurons) - Neurons that take information from the brain to the rest of the body

Organization of The Nervous System

The Central Nervous System

Our brain and spinal cord

The Peripheral Nervous System

All other nerves in our body - all the nerves not encased in bone. Two categories: The Somatic and The Autonomic Nervous Systems

Somatic Nervous System - controls our voluntary muscle movements. Controlled by moter cortex of the brain

Autonomic Nervous System - controls the automatic functions of our body-our heart, lungs, internal organs, glands, and so on. control our response to stress. Two categories: The Sympathetic and Parasympathetic Nervous Systems

• Sympathetic Nervous System - mobilizes our body to respond to stress. Carry messages to organs, glands, and muscles that direct our body's response to stress. The alert system of our body. Accelerates some functions (such as heart rate, blood pressure, and respiration) but conserves resources needed for a quick response by slowing down other functions(such as digestion)

• Parasympathetic Nervous System - Slow down our body after a stress response

Normal Peripheral Nervous System Transmission

Example:

• Stub your toe on a cast-iron coffee table
• Sensory neurons in your toe are activated
• Message transmitted to spine(Afferent Nerves)
• Message goes through spine into your brain and your Sensory Cortex
• Motor cortex sends information down the spine cord to muscles control legs and foot(Efferent Nerves)
• You hold your foot

Reflexes: An Important Exception

Reflexes do not obey the above process.

Eg. Knee-jerk Reaction. Response to intense heat or cold

THE BRAIN

Ways of Studying the Brain

Accidents - Part of the brain of a patient is damaged and the doctor is able to study the patients behavior after the damage

Eg. In 1848, a railroad worker named Phineas Gage was involved in an accident that damaged the front part of his brain. Gage's doctor took notes documenting the brain damage and how Gage's behavior and personality changed after the accident. Gage became highly emotional and impulsive after the accident. Researchers concluded that the parts of the brain damaged in the accident are somehow involved in emotional control

Lesions - Lesioning is the removal or destruction of part of the brain. It is usually not done for research purpose. Some patients have no choice but to remove part of the brain and doctors will monitor the patient after the surgury.

Eg. In the past doctors control mentally ill patients by frontal lobotomy. Lesioning part of the frontal lobe would make the patients calm and relieve some symptoms. Drugs replaced frontal lobotomies nowadays

Electroencephalogram(EEG) - Detect brain waves. Used to examine different stages of conciousness. It is widely used in sleep research to identify the different stages of sleep and dreaming

Computerized Axial Tomography(CAT or CT) - Use several X-ray cameras rotate around the brain and combine all the pictures into a detailed three-dimensional picture of the brain's structure. It is used to look for brain tumor

Magnetic Resonance Imaging(MRI) - MRI and CT both give pictures of the brain. MRI use magnetic field to measure the density and location of brain material. Bot MRI and CT only gives the structure of the brain

Positron Emission Tomography(PET) - Measure which area of the brain is most active when certain tasks are performed. It measures how much of a certain chemical parts of the brain are using. Different types of scan are used for different chemicals

Functional MRI - New technology which combines MRI and PET. Show details of brain structure with information about blood flow in the brain.

Brain Structure and Function

Three separate major categories or sections: the hindbrain, midbrain, and forebrain

Brain structure

HINDBRAIN

Controls basic biological functions

Medulla(medulla oblongata) - control our blood pressure, heart rate, and breathing. Located above the spinal cord

Pons - Connects the hindbrain with the midbrain and forebrain. Involved in the control of facial expressions. Located above the medulla and toward the front

Cerebellum - Coordinates some habitual muscle movements, such as tracking a target with our eyes or playing the saxophone. Located on the bottom rear of the brain

MIDBRAIN

This area is between the hindbrain and the forebrain and integrates some types of sensory informationand muscle movements

Reticular Formation - A netlike collection of cells throughout the midbrain that controls general body arousal and the ability to focus our attention. We will fall into deep coma if this area does not function

FOREBRAIN

Control what we think of as thought and reason. Most psychological researchers concentrate on this area

Thalamus - Receive sensory signals from spinal cord and send to other parts in the forebrain. Located on top of the brain stem

Hypothalamus - Controls several metabolic functions, including body temperature, sexual arousal (libido), hunger, thirst, and the endocrine system. Located right next to the thalamus

Amygdala and Hippocampus - Amygdala is vital to our experiences of emotion, and the hippocampus is vital to our memory system. Memories must pass through this area in order to be encoded, otherwise people cannot retain new information

Cerebral Cortex

The layer covering the rest of our brain which has fissures

Hemispheres

Contralateral Control - Two hemispheres control the other side of the body. Left controls right, right controls left

Brain Lateralization or Hemispheric Specialization - Possibility that left hemisphere may be more active during logic and sequential tasks and the right during spatial and creative tasks. This generalization requires further researches before conclusions are drawn

Split-brain Patients - Patients whose Corpus Callosum is cut in order to treat severe epilepsy.

• Researchers study Brain Lateralization by studying Split-brain Patients
• Split-brain Patients cannot orally report information on right hemisphere since the spoken language centers of the brain are usually located in the left hemisphere

Areas of the Cerebral Cortex

Association Area - Any area of the cerebral cortex that it is not associated with receiving sensory information or controlling muscle movements

Lobes of the cerebral cortex

FRONTAL LOBES

Large areas od the cerebral cortex located at the top front part of the brain behind the eyes

Prefrontal Cortex - Located at the front of the front lobe. Plays a critical role in directing thought processes. Is responsible for abstract thought and emotional control

Broca's area - Usually located at the left hemisphere of the frontal lobe. Responsible for controlling the muscles involved in producing speech. Damage of this area may cause us unable to move the muscle needed for speech

Motor Cortex - Located at the back of frontal lobe. Control voluntary movements. The bottom of this area controls the top part of the body and vice versa

PARIETAL LOBES

Located behind the frontal lobe but still on the top of the brain

Sensory Cortex(somato-sensory cortex) - Located right behind the motor cortex. Receive incoming touch sensations from the rest of our body. The bottom of this area receive information from the top of the body and vice versa

OCCIPITAL LOBES

Located at the back of the brain. Interpret messages from the eyes

TEMPORAL LOBES

Process sounds from our ears. It is not lateralized

Wernicke's Area - Interpret both written and spoken speech. Damage to this area would affect our ability to understand language. Speech might sound fluent but lack proper syntax and grammatical structure

Brain Plasticity

• If part of the brain is damaged, the other part would make new connections and take over the function of the damaged part
• Younger brains are more plastic

ENDOCRINE SYSTEM

Adrenal Glands - Produce adrenaline which signals the rest of the body to prepare for fight or flight

Ovaries and Testes - Produce sex hormones

Genetics

Basic Genetic Concepts - pass

Twins - pass

Chromosomal Abnormalities - pass