Chapter 14 Bio 251

Rostral

Meaning towards the nose, in reference to the brain, it means towards the forehead. It also means higher in the CNS.

Caudal

Means towards the tail, in reference to the brain, it means towards the spinal cord, also means lower in relation to the central nervous system

Gyrus

The elevational folds on the brain

Sulci

The shallow grooves of the brain

Mature brain anatomy sections

Forebrain,midbrain, and hindbrain

Neuralation

The development of the nervous system in the embryo

Day 19 of neurolation

The ectoderm is thickened

20 days of Neurolation

The neural groove is made

22 days of neurolation

Somites are now present

26 days of neurolation

Neural crest and tube are fully formed

Prosencephalon

Develops into the telencephalon, the optic vesicle, and the diencephalon

Mesencephalon

Develops into the midbrain

Rhobencephalon

Develops into the metencephalon and the myelinceohalon

Metencephalon

Develops into the pons and cerebellum

Myelincephalon

Develops into the medulla

The Telencephalon, optic vesicle, and Diencephalon make up the

Forebrain

The pons, cerebellum, and medulla oblongata make the

Hindbrain

Dural sinuses

The two layers are of the Dura are separated by this, they are spaces that collect blood that has circulated through the brain.

Superior Sagittal Sinus

Found just under the calvaria along the median line

Transverse sinus

Runs horizontally from the rear of the head towards each ear

Falx cerebri

Extends into the longitudinal cerebral fissure as a tough crescent shape wall between the cerebral hemispheres

Tentorium Cerebelli

Stretches like a roof over the posterior cranial fossa, and separates the cerebellum from the overlying cerebrum

Falx cerebelli

A vertical partition between the right, and left halves of the cerebellum on the inferior side

Ventricles

The four internal chambers of the brain

Lateral Ventricles

The largest and most rostral of the ventricles, it forms in arc shaped like a Ram’s horn in each central hemisphere

Interventricular foramen

A tiny pore where each lateral ventricle is connected to the third ventricle

Third ventricle

A narrow median space inferior to the corpus callosum and connected to each lateral ventricle

Cerebral aqueduct

A canal that passes down the core of the midbrain and leads to the fourth ventricle

Fourth ventricle

A small triangular chamber between the pons and cerebellum. Caudally, this space narrows in forms a central canal.

Central Canal

Formed by the fourth ventricle, it extends through the medulla into the spinal cord

Choroid Plexus

Located on the floor or wall of each ventricle, it is a spongy mass of blood capillaries. Ependymal cells lines the ventricles and canals and covers this. It produces cerebrospinal fluid.

Step 1 of CSF production and circulation

CSF is secreted by choroid plexus in each lateral ventricle

Step 2 of CSF production and circulation

CSF flows through interventricular foramina into third ventricle

Step 3 of CSF production and circulation

Choroid plexus in third ventricle add some more CSF

Step 4 of CSF production and secretion

CSS flows down cerebral aqueduct to fourth ventricle

Step 5 of CSF production and circulation

Choroid plexus in fourth ventricle adds more CSF

Step 6 of CSF Production and Circulation

CSF close down to lateral aperture and one medium aperture

Step 7 of CSF production and circulation

CSF fills subarachnoid space and baths, external surfaces of brain and spinal cord

Step 8 of CSF Production and Circulation

At arachnoid granulations, CSF is reabsorbed into Venice, blood of dural venous sinuses

Functions of CSF

Buoyancy, protection, chemical stability

Brain Barrier System(BBS)

Strictly regulates what can get from the bloodstream into the tissue fluid of the brain

Blood Brain Barrier(BBB)

The brain is protected by this, it consists of tight junctions between the endothelial cells that form the capillary walls. The endothelial cells are more selective then gaps between junctions would be, and can exclude harmful substances.

Blood CSF barrier

Formed by tight junctions between the epidermal cells. Tight junctions are absent from the epidermal cells elsewhere because it’s important to allow exchanges between the brain tissue and CSF. Protects choroid plexus

Circumventricular organs(CVOs)

Located in the third and fourth ventricles where the barrier is absent in the blood has direct access to the brain neurons. These enabled the brain to monitor and respond to floatations in blood glucose, pH, osmolarity, and other variables.

Medulla Oblongata

Is located at the caudal end of the spinal cord, it joins the spinal cord at the foramen magnum, and forms part of the ventral wall of the fourth ventricle and contains a choroid plexus too

Functions of medulla

Controls vital processes like heartbeat, breathing and blood pressure

Cardiac center

Parts of a medulla regulates the rate and force of the heartbeat

Vasomotor center

Part of the medulla, regulates blood pressure and flow by dilating and constricting blood vessels

Respiratory Centers

Part of the medulla, there are two of them, and they regulate the rhythm and depth of breathing

Pons

Form part of the anterior wall of the fourth ventricle. The fibers of disconnect, higher brain centers, and the spinal cord, and release impulses between the motor cortex and the cerebellum. They also contain the nuclear that help maintain normal rhythm of breathing.

Reticular Formation

A group of neurons that run through the mid brain, pons and medulla. It contains the rectangular activation system, keeping the cerebrum alert.

Functions of Reticular Formation

Somatic motor control, cardiovascular control, pain, modulation, sleep, consciousness, and habituation

Cerebellar Hemispheres

The right and left halves of the cerebella

Vermis

Connects to cerebral hemispheres by a worm like bridge

Folia

Tall, slender, transverse, parallel folds separated by shallow sulci, the gyrus of the cerebellum

Arbor Vitae

The white matter of the cerebellum, is exhibit a branching, Fern Lake pattern

Deep Nuclei

The white matter of the cerebellum

Cerebellar peduncles

Are connected to the brainstem by three pairs of this the inferior one is connected to the medulla, the middle one is connected to the pons, and the superior one is connected to the mid brain. These are nerve fibers that carry signals to, and from the cerebellum.

Thalamus

An overhead mass perched of the superior end of the brainstem beneath the cerebral hemisphere, it’s five parts of many functions

Anterior group of thalamus

Part of the limbic system, memory, and emotion

Medial Group of Thalamus

Emotional output of prefrontal cortex, awareness of emotions

Ventral group of Thalamus

Somatosensory, out put two postcentral gyrus, signals from cerebellum and basal nuclei to motor areas of cortex

Lateral group of thalamus

Somatosensory, out put two association of cortex, contributes to emotional function of limbic system

Posterior Group of Thalamus

Relay a visual signals to hospital lobe the lateral Geniculate nucleus an auditory signals to Temporel lobe via the medial geniculate nucleus

Hypothalamus

Forms the floor and part of the walls of the third ventricle extends anteriorly to the optic chiasm, where the optic nerve meets posterior lead to a pair of humps, called the mammillary bodie

Functions of hypothalamus

Hormone secretion, autonomic, affects, thermal regulation, food and water intake, sleep in circadian, rhythms, memory, and emotional behavior in sexual response

Epithalamus

A small mass, composed, mainly of the penal gland, to have an Ula, the midbrain, in a thin roof, over the third ventricle

Corpus Callosum

Connects the cerebral hemispheres by prominent fiber tract

Longitudinal cerebral fissure

Separates the cerebral hemispheres

The five lobes

Frontal, parietal, temporal, occipital, insula

Central sulcus

Separates frontal lobe

Frontal lobe

It is the seat of consciousness, abstract, thought, explicit, or declarative memory, cognitive, emotional processes, foresight, planning, decision, making, emotional control, and judgment of socially appropriate behavior, and most other voluntary control movements

Parietal lobe

It is connected with taste, somatic sensation, and visual processing as well as multi sensory integration

Parieto-occipital sulcus

Separates parietal lobe

Occipital lobe

The principal visual center of the brain, where we first become aware of the visuals, stimuli and processes to identify what we see

Temporal lobe

Concerned with hearing, smell, emotion, learning, language, comprehension, and memory of the grammar and vocabulary of the language we speak

Lateral sulcus

Separates temporal lobe

Insula

A small mass of cortex deep to the lateral soul, sis. It plays roles and taste, para, visceral, sensation, consciousness, emotional response, and empathy, as well as cardiovascular homeostasis.

Projection tracts

Extend vertically behind higher and lower brain and spinal cord centers. They carry information between the cerebrum and the rest of the body. The corticospinal tracts, for example, carry motor signals from the cerebrum to the brainstem and spinal cord.

Commisural tracts

Cross from one cerebral hemisphere to the other three bridges called commissures. The great majority of these tracks passed through the large corpus callosum. After which they pass through the message though smaller anterior and posterior commissures. They enable the two sides of the cerebrum to communicate with each other.

Association Tracts

Connect different regions within the same cerebral hemisphere

Long association fibers

Connect different lobes of a hemisphere to each other, such as connecting the occipital lobe to the temporal lobe

Short Association Fibers

Connect different gyri within a single lobe

Limbic system

An important center for emotion learning. It is a ring of structures on the medial side of each hemisphere, and circling the corpus callosum and thalamus. Its parts are the cingulate gyrus, the amygdala, and the hippocampus.

Basal ganglia

A mass of cerebral gray matter buried deep within the white matter lateral to the thalamus.

Three parts of basal ganglia(Corpus striatum)

Caudate nucleus, putamen, and globus pallidus

Lentiform nucleus

The putamen and the globus pallidus put together

Prefrontal cortex(frontal association area)

The most rostral part of the frontal lobe, just behind the fore head. Is the seat of judgment, intent, and control over the expression of emotions.

Primary sensory cortex

The sites were sensory input is first received, and becomes conscious of stimulus adjacent to these are association areas where this information is interpreted

Primary visual cortex

We are visual signals are received

Visual association area

Helps us with spatial awareness, recognize faces, and other familiar objects

Primary auditory cortex

Where auditory signals are received

Auditory association area

Has our ability to recognize spoken words, familiar piece of music, or a voice on the telephone

Equilibrium

Signals from the inner ear for equilibrium, project may need to the cerebellum, and several brainstem nuclei concerned with had an eye movements and visceral functions. This is the seed of consciousness of our bodies, movements and orientation in space.

Primary gustatory cortex

Taste signals are received here

Primary olfactory cortex

Smell signals are received here

General somatosensory senses

Distributed over the entire body and employ relatively simple receptors. They include senses, such as touch, pressure, stretch, movements, heat, cold, and pain.

Postcentral gyrus

When the thalamus processes, input and selectively relay signals to this body, it is a fall of the cerebrum that lies immediately post year to the central sources to the crown of the head, then down into the longitudinal cerebral Fissure

Primary somatosensory cortex

The cortex of the postcentral gyrus

Somatosensory association area

Call due to the virus and the roof of the lateral sources. Awareness of stimulation occurs here, but making cognitive sense of it.