The Human Brain

Basic Brain Structure Composed of 100 billion cells Makes up 2% of bodies weight Contains 15% of bodies blood supply Uses 20% of bodies oxygen and glucose

Brain Protection Surrounded by the cranium Surrounded by protective membranes called meninges Fluid within the spaces of the meninges called, cerebral spinal fluid (CSF)

Major Parts of The Brain

Medulla Oblongata Attached to the spinal cord at the base of the brain Contains reflex centers for vomiting, hiccupping, coughing, and swallowing.

Contains control centers for: 1.Heart rate 2.Force of heart contractions 3.Blood pressure 4.Breathing rate

Cerebellum

The cerebellum processes input from other areas of the brain, spinal cord and sensory receptors to provide precise timing for coordinated, smooth movements of the skeletal muscular system.

Thalamus

The sensory relay center of the brain. Receives sensory information from parts of the body and directs these messages to the appropriate parts of the brain

Hypothalamus

Main control center for the autonomic nervous system. Also controls feelings of hunger, body temperature, aggression, sex drive, thirst, circadian rhythms, fear, control of sex hormones Secretes hormones that control the pituitary gland

Midbrain

Important visual and auditory functions Controls eye movements Important functions dealing with movement.

Pons

Functions include: 1.Arousal 2.Sleep 3.Level of consciousness 4.Assist in control of autonomic functions.

Limbic System

The limbic system encompasses structures that are critical for forming memories and experiencing pleasure, as well as for various motivational and emotional activities.

The Cerebrum Largest part of the Human Brain This part of the Brain has many convolutions that give it a very large surface area.

Functions of the Cerebrum: All information from our senses are sorted and interpreted in this part of the brain

Voluntary muscles that control movement and speech are contained in the cerebrum

Memories are stored in the cerebrum The cerebrum is the decision making part of the brain. The cerebrum is thought to be the center of human consciousness

Regions of the Cerebrum Cerebral Cortex – The outer lining of the cerebrum The cerebral cortex has several important functions

1.Experience of sensation 2.Voluntary movement 3.All thought processes associated with consciousness

Cerebral Hemispheres The cerbral cortex is organized into two halves called hemispheres, the right and the left. A structure called the corpus callosum bridges the right and left hemispheres (250 million nerve fibers)

Corpus Callosum

Right vs. Left Hemisphere Voluntary muscles on one side of the body are controlled by nerves in the opposite hemisphere of the brain.

The same generally holds true for sensory information. For example things seen in the left eye are processed on the right side of the brain.

Hemispheric Dominance Close to 90% of the population is right handed. Most of us also show dominance with respect to our legs, eyes, and ears.

Each hemisphere of the brain is also dominant for other behaviors :

Left Hemisphere Language Math Logic

Right Hemipshere Spatial abilities Face Recognition Visual imagery Music

These are merely generalizations as both sides of the brain work together to perform most functions

Lobes of the Cerebral Cortex The cortex of the Cerebrum is divided into Four Lobes: 1.Frontal Lobe 2.Parietal Lobe 3.Temporal Lobe 4.Occipital Lobe

Frontal Lobe Control of voluntary muscles Reasoning Critically thinking

Parietal Lobe Receives sensory information from from skin and skeletal muscles Associated with sense of taste

Temporal Lobe Perception and recognition of auditory stimuli Memory

Occipital Lobe Concerned with many aspects of vision.