Structures of the Brain

Welcome To Your Brain! Your brain is the central site of processing in the entire body It is responsible for the majority of thoughts and actions that happen in your body What makes you act and think like you, is the neurons in your brain

Welcome To Your Brain! A typical brain is around 3lbs and contains around 97% of the bodies neural tissue Male brains are typically around 10% larger However that has no link between brain size and intelligence Brains can vary greatly in size from 750ml to 2100ml with a normalized average of 1200ml

Welcome To Your Brain! Your brain has a unique ability to structure its neurons to be able to interpret and understand the world around us The structure of the neurons dictates what our brains do At the same time, the structure of our neurons can often mislead us… https://www.youtube.com/watc h?v=sxwn1w7MJvk https://www.youtube.com/watc h?v=rN7AN0GnwqI https://www.youtube.com/watc h?v=tjFxMKEkGjE&index=21&list =PLCv6T8QWRwjkkK_fbUcV8V6 Qb2L4xpJSU

Video The only way to experience the brain is through seeing one This is a surgery of a bleed that is disrupting brain function sent by a student WARNING… it is surgery WARNING… it is bloody WARNING… You will see the bleed where the blood is coming from However, it is really cool! https://www.youtube.com/watch? v=Ji7fohBEPnM&app=desktop

Parts of the Brain The brain is split into seven major sections These sections include The cerebellum The medulla oblongata The pons The midbrain The diencephalon The cerebrum The Hippocampus

Parts of the Brain The cerebrum is considered the “adult brain” and it is located outside all of the other brain materials It is covered by layers of scrunched cerebral cortex Cortex is latin for bark The cerebrum is responsible for higher mental functions like thoughst, intellect, memory and complex movements

Parts of the Brain The cerebrum is also divided into two different hemispheres The right side of the cerebrum is separate from the left side of the cerebrum The two sides of the brain are called hemispheres They communicate in an area called the corpus callosum https://www.youtube.com/watch?v=lfGwsAdS9Dc https://www.youtube.com/watch?v=ZMLzP1VCANo

Parts of the Brain The cerebellum is partially hidden by the cerebral hemispheres and is located in the dorsal part of the brain It has a variety of jobs inside of the motor system However, the most important is how it coordinates complex motor functions based on previous motor functions This helps you learn and repeat major functions

Parts of the Brain The spinal cord connects to the brain at the medulla oblongata The inferior portion of the medulla oblongata resembles the spinal cord This is the lowest part of the brain stem The medulla oblongata has two main functions It relays spinal information to the rest of the brain It is responsible for autonomic function such as heartbeat, blood pressure and digestion *Alligators are not ornery because of their medulla oblongata - https://www.youtube.com/watch?v=cu7A8LIzL1o

Parts of the Brain The pons connects the cerebellum to the inferior parts of the brain stem The pons helps divert certain sensory information to the cerebellum and thalamus The pons give you subconcous control over visceral and somatic motor centers

Parts of the Brain The midbrain (mesencephalon) is superior to the pons It serves many purposes It is a sight for processing some visual and auditory information It is responsible for most cranial reflex procession It is also important for maintaining consciousness

Parts of the Brain The diencephalon contains both the thalamus and the hypothalamus The thalamus is an important site for both incoming and outgoing processing of sensory information The hypothalamus is rooted in hormone production, emotion and autonomic functions The hypothalamus connects the pituitary gland This is where the nervous system and endocrine system link https://www.youtube.com/watch?v=O-rQ3tIabvM

Parts of the Brain The hippocampus is a very small section of the brain, however it is a vital section in humans The hippocampus is located within the brainstem and is associated with memory, learning and special recognition Patients who suffer from Alzheimer's disease suffer from damage to the hippocampus

Development of the Brain To fully understand the internal organization of the adult brain we must consider its origins The nervous system begins as a hollow tube known as the neural tube The tube has a fluid filled internal cavity called the neurocoel

Development of the Brain During early development the neurocoel enlarges in three distinct areas These sections of the brain form around 3 weeks of age These create the primary brain vesicles Each is named for the position that it takes relative to the others

Development of the Brain The prosencephalon is the most forward of the three Also called the forebrain Proso means forward Enkephalos means brain The mesencephalon is the middle segment Also called the midbrain The rhombencephalon is the is the most inferior (location) of the three Also known as the hindbrain

Further Developments In later stages of development the prosencephalon and rhombencephalon are subdivided further The new divisions are called secondary brain vesicles Each divides into two distinct sections This gives the brain five distinct divisions at 6 weeks

Further Developments The prosencephalon forms the telencephalon (anterior) and the diencephalon (posterior) The telencephalon ultimately forms the cerebrum of the adult brain The diencephalon (as we already know) contains the thalamus, the hypothalamus and the pituitary gland

Further Developments The rhombencephalon adjacent to the mesencephalon forms the metencephalon The dorsal portion of the metencephalon will become the cerebellum and the ventral portion will develop into the pons The portion of the rhombencephalon closer to the spinal cord forms the myelencephalon This will become the medulla oblangata

Diagram

Ventricles of the Brain Neurocoel eventually expands in the growing and developing brain The neurocoel eventually expands to form enlarged chambers within the brain These chambers are called ventricles

Ventricles of the Brain There are four major ventricles that are located within the brain Each hemisphere contains a large lateral ventricle This is formed by the telencephalon through development

Ventricles of the Brain The next ventricle that is seen is the third ventricle Remember that there are two lateral ventricles! The third ventricle is located within the central region of the brain It is formed by the diencephalon

Ventricles of the Brain The two lateral ventricles and the third ventricle communicate through the interventricular foramen This is a small set of tubing that links the two lateral ventricles with the central third ventricle

Ventricles of the Brain The fourth ventricle contains sections of the pons, cerebellum and the medulla oblongata It also narrows and becomes continuous with the central canal of the spinal cord This is formed by the metencephalon and the myelencephalon The fourth ventricle connects to the third ventricle by the cerebral aqueduct

Video https://www.youtube.com/watc h?v=Zm-TsqsgCHc Obviously med school students (or similar) for a project…

Cranial Meninges The layers that make up the cranial meninges are similar to the ones that make up the spinal meninges However there are some differences on how they are structured This is because of the level of protection and care that the body uses with the brain

Cranial Meninges The cranial dura mater consists of out and inner fibrous layers The outer layer (superior dura mater) is fused to the cranial bones giving it an anchor point The inner layer (inferior dura mater) is separated from the outer layer by a small gap that contains fluids and blood vessels The gap is called the dural sinus

Cranial Meninges The cranial arachnoid mater consists of the arachnoid membrane and the cells that cross the sub arachnoid space These cells are called arachnoid trabeculae This creates a smooth layer around the brain that does not follow all of the ridges of the cranial cortex

Cranial Meninges The pia mater sticks to the surface of the brain It anchors itself to the intricate folding patterns of the brain It also travels with branches of the cerebral blood vessels that penetrate the surface of the cerebral cortex This allows it to keep blood from the brain

Video Things can go wrong… https://www.youtube.com/watc h?v=zCCD52Pty4A Then they can go really wrong… http://www.dailymotion.com/vi deo/x17ha6y_monsters-inside- me-s03e03-my-face-eating- parasite_lifestyle Start at 30:48