Biological Level of Analysis . Biological Level of Analysis

Neuron Basic unit of the brain

Neuron Cell body – source of life of the cell Dendrites – branches on the cell bodies that act as receivers of messages from adjacent neurons. Axon – projection through which messages travel. Synaptic knobs: Tips of branches at end of axon. Sends messages to adjacent neurons. Synapse: Fluid filled gap between neurons. The form of the messages are electrochemical, for example neruotransmitters. Show diagram of a neuron.

Cortex Upper and largest portion of the brain (80%) Involved in higher order intelligence, memory, and personality Composed of two hemispheres (duplicated with some differences) Left hemisphere – language, speech, writing, logic, comprehension, calculation Right hemisphere – visuospatial, drawing, face recognition, holistic thought

Four lobes of the cerebral cortex Temporal Hearing Vision Smell Memory Frontal Responsibility Higher level intelligence Planning Problem solving Emotions Self-awareness Parietal Bodily sensations, e.g., pain, heat Body movement Occipital Primary visual area of the brain Each lobe appears to have its own memory storage area. Basal ganglia are part of the cerebrum, embedded deep within the cerebrum, the main portion of the brain, and are responsible for orderly, smooth, purposeful movements.

Sub Cortical Structures Cerebellum – balance and muscle control Hypothalamus – regulates biological needs such as hunger and thirst, temperature control, pleasure and sexual excitement. Amygdala (emotion, aggression) Hippocampus (memory and learning) Thalamus - chief relay centre for directing sensory messages helps regulate awareness. Relays commands going to the skeletal muscles from the motor cortex. Cerebrum = sensing, thinking, learning, voluntary movement Brain Stem = Vital for function (Pons, R.F., Medulla)

Medulla – vital functions controls heart rate, blood pressure and respiration Pons – involved in sleep and arousal, eye movement, facial expressions Reticular formation – group of fibres that carries stimulation related to sleep and arousal through brain stem Pituitary Gland – “Master Gland” regulates other endocrine glands Nucleus Accumbens – motivation and reward Corpus Callosum – bridge of fibres passing information between two hemispheres Thalamus – relay centre for incoming sensory information

Spinal cord Transmits messages from the brain to the other areas of the body. Efferent – away from the brain out to the body Produces muscle action Afferent – from the periphery to the brain Relays information from the sensory organs Extends down from the base of the brain stem. Disorders of the spinal cord include poliomyelitis, paraplegia, and quadriplegia. Poliomyelitis is a viral disease that attacks the spinal nerves and destroys the cell bodies of the motor neurons. This means that impulses cannot be carried from the spinal cord to the body. Consequences may be difficulty walking, can be as severe as paralysis. Paraplegia is paralysis of the lower extremities of the body and occurs when the lower portion of the spinal cord is damaged. Quadriplegia is paralysis of all four limbs and the trunk of the body. It occurs when the upper portion of the spinal cord is severed. When the spinal cord is severed, impulses can’t travel from the brain to the periphery or back to the brain from the periphery. The person usualy looses bladder and bowel control.

http://hopes.stanford.edu/sites/hopes/files/brain.swf