biology 211 anatomy & physiology i the brain
TRANSCRIPT
Biology 211Anatomy & Physiology I
The Brain
Human Central Nervous System
Starts as a hollow tube in the embryo;Remains hollow & fluid-filled throughout life;These spaces form the ventricles of the brain and the central canal of the spinal cord.
Cranial end of this hollow tube enlarges & folds to form brain and its various parts
Caudal end of this hollow tube does not enlarge or fold;Develops into spinal cord
Embryology of nervous system
From lab, you should understand what adult structures form from the myelencephalon metenchephalon mesencephalon diencephalon telencephalon
Prosencephalon
Rhombencephalon
More terms you need to know for brain and spinal cord
Nervous tissue of the CNS consisting of neuron cell bodies, their supporting glia, and unmyelinated axons & dendrites.
Nervous tissue of the CNS consisting of myelinated axons & dendrites and their supporting glia
A region of gray matter on the surface of the brain (found only on the cerebrum and cerebellum) A deeper region of gray mattter, surrounded by white matter
Coronal Section of Brain
Cross Section of Spinal Cord
The brain has seven major (and many minor) regions: Cerebrum Thalamus Hypothalamus Midbrain Pons Cerebellum Medulla Oblongata
Let’s discuss each of these briefly.
Thalamus develops from diencephalon
Most nuclei are relay centers:Receive sensory information from spinal cord, other regions of brain, eyes, ears, tongue, nasal epithelium. Relay that to sensory regions of cerebral cortex
Some nuclei relay motor information from cerebral cortex to other regions of brain
Some nuclei regulate sleep/wakefulness
Hypothalamus develops from diencephalon
Some nuclei regulate body temperature, blood pressure, hunger, thirst, fatigue.
Some nuclei regulate endocrine (hormone) functions by controlling activity of pituitary gland (to which it is connected)
Midbrain develops from mesencephalon Often still called that.
Some nuclei regulate eye movement & visual reflexes.
Large tracts of white matter (myelinated axons) pass through, carrying motor information from cerebral motor cortex toward other parts of brain and spinal cord.Some nuclei modify that information to regulate motor functions.
Large tracts of white matter pass through, carrying sensory information from spinal cord toward thalamus.
Pons develops from metencephalon
Some nuclei relay signals between cerebrum and cerebellum.
Some nuclei help regulate sleep, respiration, swallowing, taste, hearing, bladder control, equilibrium, eye movement, facial expressions, facial sensation, and posture.
Motor information from cerebral cortex (white matter) continues toward medulla oblongata and spinal cord; sensory information continues from the medulla oblongata and spinal cord toward the thalamus and toward the cerebellum.
Cerebellum develops from metencephalon
Nuclei and cortex receive both motor information (from cerebral cortex and nuclei of other parts of brain) and sensory information spinal cord and other parts of the brain. Uses that information to coordinate and fine-tune movement, particularly timing and precision.
White matter carries that information to and from nuclei and cortex.
Medulla Oblongata develops from myelencephalon
Some nuclei help regulate respiration, heart rate, blood pressure, blood distribution.
Other nuclei regulate vomiting, coughing, sneezing, swallowing.
White matter carries motor information from other regions of brain to spinal cord, and sensory information from spinal cord to other regions of brain.
Cerebrum
Arises from the telencephalon
Consists of right and left hemispheres separated from each other by the
Each hemisphere is hollow, containing a which is lined by ependyma and filled with cerebrospinal fluid
Cerebrum
Each hemisphere Includes both white matter and gray matter:
Coronal Section
Cerebral Cortex
Gray Matter2 - 4 mm thickFolded into ridges, or (singular: ) separated by shallow grooves, or (singular = )Different parts of brain separated by deep
Lobes of Cerebral Cortex
Cerebral Cortex
Each gyrus, sulcus, and fissure has a name (more than 50 gyri & sulci)
Cerebral Cortex
Each gyrus, sulcus, and fissure has a name You don't need to know all of them
You will need to know the following:
Central SulcusPrecentral GyrusPostcentral Gyrus
Longitudinal Fissure
Parietooccipital SulcusLateral Fissure/Sulcus
Cerebral Cortex
Different regions of the cortex have specific functions
Three types of functional areas: Motor Sensory Association
Cerebral Cortex
Different regions of the cortex have specific functions
From your reading and lab exercises, you should know the functions of the following areas and where they are located: Primary somatosensory area Somatosensory association area Primary motor area Motor association area Primary visual area Visual association cortex Primary auditory area Auditory association area
Questions on these may be on lecture and/or lab exams
Cerebral Cortex
Different regions of the cortex have specific functions
Two regions of cortex important in language:
deals with formation of speech
deals with recognition and interpretation of speech
Both located primarily onjust one hemisphere(usually the left).Similar regions on other hemisphere control emotional content of speech.
Cerebrum
Recall::Gray matter forms both: Cortex
Basal Nuclei
Coronal Section
Cerebral Nuclei
Basal or Deep or Cerebral Nuclei
Not shown:
From your reading and lab exercises, you should also know the locations of the
- Lateral ventricles - Interventricular foramen - Third ventricle - Fourth ventricle - Mesencephalic aquaduct - Median aperture - Lateral apertures
Questions on these may be on lecture and/or lab exams
Brain is surrounded by three layers of connective tissue:
Mater
Mater
Mater
(Skull)
Space
Space
Space
The brain is protected in three ways:
1)
2)
3) Floats in
Cerebrospinal fluid produced within ventricles by specialized tissue called
Flows toward fourth ventricle
Exits from fourth ventricle through three openings (apertures or foramina) into the subarachnoid space.
Two
Surrounds brain & spinal cord.
Reabsorbed into blood through arachnoid villi on surface of brain