Quiz 1- Lecture 1: Anatomical Overview of the Human Brain: CNS Flashcards
The adult human brain weighs approximately…
What percent of body weight does it make up?
1 and a half kilograms
Less than 2%
The brain is responsible for…
generation of language and thought, attention, consciousness, memory, and imagination
Why is the brain highly folded?
In order to fit into the skull and accommodate the massive number of neurons and connections needed
What are gyri?
What are sulci?
Ridges
Furrows
If we were to unfold the human brain, it would take up…
1 square meter
“Most impressive feature of the brain”
How many neurons in the brain?
Amount of connections formed between neurons
~86 billion neurons, each of which forms an average of 7,000 connections with other neurons, resulting in between 100 and 500 trillion synapses within the brain
The brain can be divided into what regions? (2)
Functional and anatomical
Anatomical overview:
The different surfaces of the brain
Superior surface (top)
Inferior surface (bottom)
Anterior aspect (in front)
Posterior aspect (in back/behind)
Axes within the CNS:
Connections can travel which ways (2)?
Towards the anterior pole (front of brain)
or
Towards inferior end of the spinal cord (back of brain to neck)
Axes within the CNS:
Fibers can move which ways (2)?
Rostrally (towards the rostral pole)
or
Caudally (towards the caudal pole)
Component parts of the brain:
Forebrain (composed of cerebral hemispheres and deep structures)
Right and left hemispheres roughly symmetrical and connected through Corpus Callosum
What is the largest white matter tract in the brain?
How many estimated projections?
Corpus callosum
200-250 million projections
Thalamus and hypothalamus make up what?
Diencephalon
The cerebral hemispheres and diencephalon together comprise
Forebrain
Brain stem: (caudal to the diencephalon)
Divided into 3 parts:
Midbrain (caudal to thalamus), Pons (caudal to midbrain), Medulla (most caudal part of brain stem; continuous with spinal cord as it exits foramen magnum of skull)
Parts of the midbrain:
Cerebral peduncles (connect the Forebrain with all caudal structures)
Pons is connected to
(Also embryologically part of pons but functions are so distinct that it’s now considered its own entity separate from brainstem)
Cerebellum (through the cerebellar peduncles)
The cerebral hemispheres can be divided into lobes along key surface landmarks.
Central sulcus separates…
Frontal lobe from the Parietal lobe
The lateral fissure separates…
Temporal lobe from both Frontal and Parietal lobes
The occipital lobe is separated from the parietal lobe via the
Parieto-Occipital sulcus (seen on medial aspect of brain)
Continuous strip of cortex which swings around surface of the brain:
What does it span?
Limbic lobe
Spans the frontal, parietal, and temporal lobes
Deep within brain, spaces filled with
Cerebrospinal fluid (CSF)
C shaped lateral ventricles in cerebral hemispheres have
An anterior horn, a posterior horn, and an inferior horn
Lateral ventricles are connected to
3rd ventricle in the midline
What is the 3rd ventricle connected to and through what?
The 4th ventricle; through the Cerebral Aqueduct
Midsaggital section of brain: different components of ventricular system
Lateral ventricle, Third ventricle (thalamus on either side) connects to the Fourth ventricle (at level of Pons and Medulla) via Cerebral Aqueduct
Planes that brain can be sectioned in
Coronal plane (slicing like bread from front)
Horizontal plane (cutting from above)
Saggital plane (slicing middle- only middle is midsaggital)
What can you see in coronal plane?
Corpus callosum (front), Anterior horn of lateral ventricle
Head of caudate nucleus, Putamen, Anterior limb of internal capsule
Lateral ventricles, Third ventricle (on either side of thalamus)
Cerebral aqueduct, Inferior horn of lateral ventricle
(Posterior) Thalamus, Midbrain, Pons
In coronal section, you can see 2 types of matter.
What are they?
White matter: sum of all myelinated axons or tracts as they travel through the CNS
Gray matter: sum of all nerve cell bodies (seen along cortical band along surface of the brain)
