Anatomy of the Human Brain Department of Biology and Human Anatomy and Physiology Department of Biology and Human Anatomy and Physiology Mission Hills High School Mission Hills High School

The Human Brain The human brain is a gelatinous three-pound lump of fat, connective tissue, spinal fluid and nerve cells. ( So, if someone calls you a fat head, don’t worry about it, it’s the truth!) Its neurons generate some 25 watt of total power. It is in contact with every living cell in the body. It feels no pain!

The Human Brain The human brain is a greedy, thirsty, selfish vampire that guzzles a pint- and-a-half of blood a minute. No matter what is happening to the body, the brain takes its nourishment first. For unknown reasons, the brain needs more blood when the body is asleep than when awake. One minute without oxygen or glucose results in unconsciousness 8 minutes without oxygen causes death

The Brain Has Three Main Anatomical Divisions: Forebrain (cerebrum) Forebrain (cerebrum) Midbrain Midbrain Hindbrain (pons, medulla and cerebellum) Hindbrain (pons, medulla and cerebellum)

Three Functional Divisions: CerebrumCerebellumBrainstem Sensory muscle coordinationvital regulations and motorand balanceheart, lungs, GI

The Brainstem Includes the midbrain Includes the midbrain The pons The pons Medulla Medulla Found in the brainstem is the Reticular Formation which regulates vital centers: heart, lungs, stomach, intestines and glands. Found in the brainstem is the Reticular Formation which regulates vital centers: heart, lungs, stomach, intestines and glands. Injury to the RF causes instant death. Injury to the RF causes instant death.

The Cerebrum The cerebrum Is the largest part of the brain The cerebrum Is the largest part of the brain Weighs lbs Weighs lbs Contains the cortex Contains the cortex Surface of cortex convolutions called gyri and infolds called sulci Surface of cortex convolutions called gyri and infolds called sulci Gyrus; Sulcus = Singular form Gyrus; Sulcus = Singular form Some sulci are pronounced and help form boundaries for the cerebral lobes Some sulci are pronounced and help form boundaries for the cerebral lobes Thalamus Thalamus Hypothalamus Hypothalamus

Gyri, sulci and lobes of the cerebrum

The Cerebrum The cortex is an integrating area The cortex is an integrating area Brings together afferent (sensory) information Brings together afferent (sensory) information Forms complex perceptual images Forms complex perceptual images Ultimate control over autonomic and somatic systems Ultimate control over autonomic and somatic systems

The Cerebrum Thalamus contains part of the Reticular Formation Thalamus contains part of the Reticular Formation Is a relay station for all incoming info. (except smell) Is a relay station for all incoming info. (except smell) Sends info to correct part of the cortex Sends info to correct part of the cortex Concerned with emotions and motivation Concerned with emotions and motivation

The Cerebrum Hypothalamus is also concerned with emotions and motivation Hypothalamus is also concerned with emotions and motivation Single most important regulation of internal environment (maintains homeostasis) Single most important regulation of internal environment (maintains homeostasis) Regulates temp, water balance, pituitary functions Regulates temp, water balance, pituitary functions Food intake, gastric secretions Food intake, gastric secretions

End Part I

Learning and The Brain Department of Biology and Department of Biology and Anatomy and physiology Anatomy and physiology Mission Hills High School Mission Hills High School

Hemispheres The Brain has two sides: The Brain has two sides: Left hemisphere Left hemisphere Right hemisphere Right hemisphere Left brain controls the right side of the body Left brain controls the right side of the body Right brain controls the left side of the body Right brain controls the left side of the body Left handed people are the only ones in their “right mind”! Left handed people are the only ones in their “right mind”!

Left side: Deals in Time Thinking process in sequence Thinking process in sequence Logic Logic Words Words Past, Present, Future Past, Present, Future

Right side: Deals with space Thinking process in space Thinking process in space Wholeness (ability to sense the whole thing) Wholeness (ability to sense the whole thing) Patterns Patterns Visual concepts Visual concepts Now Now

Everyone is born with 2 hemispheres One will develop more than the other One will develop more than the other Which ever is used most, is the side that will develop most Which ever is used most, is the side that will develop most If mother relates words at feeding time, left brain develops If mother relates words at feeding time, left brain develops If mother relates space ( large room, out doors) at feeding time, right brain develops If mother relates space ( large room, out doors) at feeding time, right brain develops

Everyone is born with 2 hemispheres 90% of the population is left brain 90% of the population is left brain 9.9% of the population is both sides to some degree 9.9% of the population is both sides to some degree Very few are completely right brain Very few are completely right brain

Here’s an example of both sides working together: If you don’t perceive any illusions within the pattern, you are complete right sided If you don’t perceive any illusions within the pattern, you are complete right sided If you see an illusion within the patterns that move constantly as you move your eyes through the images, you are left sided If you see an illusion within the patterns that move constantly as you move your eyes through the images, you are left sided If you see a staggering illusion, you are both right and left sided! If you see a staggering illusion, you are both right and left sided!

Cool! Let’s see what happens when one side of the brain becomes fatigued and the other side does not… Let’s see what happens when one side of the brain becomes fatigued and the other side does not… Look at the clouds for about a minute. You will notice that it is not moving. Look at the clouds for about a minute. You will notice that it is not moving. I will show you a moving pattern for about 2 minutes. Stare at the center. I will show you a moving pattern for about 2 minutes. Stare at the center. Then I will return the still photograph of the clouds Then I will return the still photograph of the clouds

End Part 2

Central Nervous System

Cranial Nerves

Dorsal Root Ganglion

Where is the Central Fissure?

Gross Anatomy (What View of the Brain?)

Meninges and Cerebral Veins

The Dura Mater and a Compressing Meningioma

Pia Mater

Cerebrovascular System