Lecture 1 -- Central Nervous System (CNS) Overview

What does the Central Nervous System (CNS) consist of?

Brain and spinal cord

What protects the brain and spinal cord?

Bony structures and meninges

What structures belong to the forebrain?

Cerebrum, thalamus, hypothalamus, pituitary gland, limbic system and olfactory bulb

What structures belong to the hindbrain?

Pos, Medulla oblongata and cerebellum

What does the CNS form from?

From Rostral neural tube → Vesicles

What structures are derived from the forebrain?

Prosencephalon → Telencephalon → Cerebrum

Prosencephalon → Diencephalon → Thalamus, hypothalamus

What structures are derived from the mesencephalon?

Mesencephalon → Mesencephalon → Midbrain

What structures are derived from the rhombencephalon?

Rhombencephalon → Metencephalon → Pons, cerebellum
Rhombencephalon → Myelencephalon → Medulla oblongata

Where does the closure of the neural tube begin?

Closure begins in the cervical region

Rostral end of the neural tube that form the brain has to fold up in a certain way in order to fit into the skull → Three main flexure form. What are they?

1. Cephalic flexure

2. Pontine flexure

3. Cervical flexure

What separates the left and right cerebral hemispheres?

Longitudinal fissure

What separate the cerebrum from the midbrain and cerebellum

Transverse fissure

What is the function of cerebrospinal fluid (CSF)?

Nourishment, waste removal, protects the brain

What is the condition when the neural tube doesn't close?

Encephalocele

1. Spinal bifida = Vertebrae has not fully formed

2. Meningocele = Dura on the outside the spinal cord has not fully formed ? Cause the CSF in arachnoid bulge outwards

3. Meningomyelocele = More sever condition of meningocele → Spinal cord tissue is prolapsed out

What does gray matter consist of?

Cell bodies, dendrites, and synapses

What does white matter consist of?

Axons

In brain, where do the grey matter and white matter located?

Grey matter: Outside cortex

White matter: Inside the brain

In spinal cord, where do the grey matter and white matter located?

Grey matter: Inside

White matter: Outside

What are clusters of cell bodies called in the CNS and in PNS?

CNS: Nuclei

PNS: Ganglia

What are bundles of axons called in the CNS and in PNS?

CNS: Tracts

PNS: Nerves

What are clusters of cell bodies called in the PNS?

Ganglia

What are gyri?

Ridges

What are sulci?

Furrows

What are folia?

Folds of the cerebellum → Grey matter is within it

What is the white matter branches in cerebellum?

Arbor Vitae/ Tree of life

What are the lobes of the brain?

What happens in holoprosencephaly? What causes holoprosencephaly?

Forebrain fails to divide into two hemispheres = No longitudinal fiexure can be seen

Caused by corn lily ingestion

What are ventricles of the brain?

Spaces in the brain where CSF circulates

→ Spinal cord → Central canal → Fourth ventricle → Lateral ventricle → Third ventricle → Mesencephalic aquaduct → Fourth ventricle → Central canal

Which structure connects the third and fourth ventricles?

Mesencephalic aqueduct

What happens with hydrocephalus?

Increase pressure on the region of mesencephalic aqueduct → Block the drainage of cerebrospinal fluid → Build up of CSF in brain → Affect the pressure on the brain tissue + development

Where is the auditory cortex located?

Sits dorsal aspect of the temporal lobe

Where is the visual cortex located?

Sits at the occipital lobe

Where is the motor cortex located? What is it responsible for?

Sits at the caudal portion of the frontal lobe

Responsible for muscle contraction

Where is the somatosensory cortex located? What is it responsible for?

Rostral portion of the parietal lobe

If we touch somethings, signals are sent to this cortex to process that information

Apart from motor, auditory, visual and tomato-sensory cortex. What is the remaining part of the brain named? What is its function?

Association cortex

→ Integrates experiences with memories and emotion

What structures does rhinencephalon include?

Olfactory bulb, olfactory tracts, olfactory peduncle, piriform lobe, hippocampus and fornix

What is the function of rhinencephalon?

Sense of smell + Communicates with higher centre to affect emotion, behaviour and communication

Identify the key structure of rhinencephalon.

What is the function of frontal cortex?

Involved in decision making, planning, motivation, personality, memory

What are the function of temporal lobe?

Hearing, feeling, learning and fear

What are the functions of parietal Lobe?

Smell, touch, taste, language

What are the functions of the occipital lobe of cerebrum.

Vision

What is the function of limbic system?

Series of tracts and nuclei for emotion, learning and memory

What is the function of basal nuclei = Corpus striatum?

Planning and executing movement

What is the function of hypothalamus?

Endocrine and nervous system

What is the function of thalamus?

All sensory information except olfactory input + Sleep and wakefulness

What structure is this in cerebellum?

Central cerebellar = Vermis

What are the functions of cerebellum?

Coordinates gait, maintains posture, controls muscle tone and voluntary muscle activity → Balance and coordination

NOT for muscle contraction

What are the functions of midbrain?

Include tectum → Orientate the head and body in response to sights and sounds

What are the function of brainstem?

Cardiovascular, respiratory and GI function

Why are the olfactory bulbs so much larger in dogs than in humans?

Important for survival