Central Nervous System (copy)

What composes the CNS?

Brain and spinal cord

What is the role of afferent nerves?

Receive stimuli from receptors and send to CNS

What is the role of efferent nerves?

Send information to effectors

What are the two types of effectors in the body?

Mechanical (muscle) and chemical (glands)

What are the three types of receptors in the brain?

Interoceptors, proprioceptors, and exteroceptors

Where do interoceptors receive information from?

Organs

Where do proprioceptors receive information from?

Limbs (touch)

Where do exteroceptors receive information from?

Sensory organs (vision, smell, hearing)

What are the three general functions of the brain?

Receive information, process information, and send instructions for response

What is the general function of the spinal cord?

Transmit stimuli to/from brain to PNS

What is the specialized lining of the CNS?

Meninges

Which embryonic layer are the meninges derived from?

Ectoderm

What are the three layers of meninges, from outside to inside?

Dura mater → arachnoid mater → pia mater

Describe the dura mater.

Tough and fibrous

Describe the pia mater.

Only a few cells directly on the surface of the brain.

What is the space between the arachnoid and pia mater?

Subarachnoid space

What does the subarachnoid space contain?

Cerebrospinal fluid

Look at the meninges

I have looked

Look at the meninges again

I have looked again

What are the chambers within the brain called?

Ventricles

What are the ventricles in the brain filled with?

Cerebrospinal fluid

What structure makes CSF?

Choroid plexus

What are the three ventricles in the brain, from cranial to caudal?

Lateral → third → fourth

What is the function of CSF?

Protects brain

What is the structure of the choroid plexus?

Tufts of blood vessels

What type of cells form the choroid plexus?

Ependymal cells

What shape are ependymal cells?

Cuboidal

Look at this photo of the choroid plexus

I have looked at the choroid plexus

What is CSF composed of?

Fluid, electrolytes, small proteins/hormones, glucose, neurotransmitters

Which cells have a tight cellular junction and create the blood-brain barrier?

Ependymal cells

What is the blood-brain barrier? Why do we have it?

Separates brain from rest of body → prevents pathogens from entering brain

Fish only have one meninx.

ok

Amphibians, reptiles, and birds have which two layers of meninges?

Dura mater + secondary meninx

In mammals, what does the secondary meninx become?

Arachnoid and pia mater

Which embryonic layer is the brain derived from?

Ectoderm

What are the three embryonic regions of the brain, from cranial to caudal?

Prosencephalon (forebrain) → mesencephalon (midbrain) → rhombencephalon (hindbrain)

What does the prosencephalon divide into?

Telencephalon and diencephalon

What does the rhombencephalon develop into?

Metencephalon and myelencephalon

Why does the embryonic neural tube fold?

To increase surface area

What does the telencephalon differentiate into?

Cerebral hemispheres, hippocampus, and olfactory system

What does the diencephalon differentiate into?

Thalamus, hypothalamus, pituitary gland, pineal gland, retina, optic nerve, mammillary bodies

What does the mesencephalon differentiate into?

Midbrain

What does the metencephalon differentiate into?

Pons and cerebellum

What does the myelencephalon differentiate into?

Medulla

Which embryonic segment of the brain is ubiquitous among species?

Rhombencephalon

Which embryonic segment of the brain is enlarged in sharks, rays, and mammals?

Olfactory bulbs

Which embryonic segment of the brain is enlarged in tetrapods?

Forebrain

What are the three functions of the medulla oblongata?

• Contains cranial nerve 6-12 cell bodies

• Visceral, autonomic reflexes → respiration, heartbeat

• Pathway for ascending stimuli to higher brain and descending stimuli to spinal cord

What is the function of the pons?

Transmit information between cerebellum and cerebral cortex

What type of information does the pons transmit?

Position

What are the functions of the cerebellum?

• Maintain equilibrium/balance

• Process sensory input

• Motor action and learning

Which part of the brain is well-developed in organisms that must survive in currents and stay upright?

Cerebellum

What are the branches on the cerebellum known as?

Arbor vitae

What is the function of the mesencephalon?

Receive and process sensory stimuli

What are the superior and inferior portions of the mesencephalon?

Tectum and tegmentum

The optic tectum receives which type of stimuli?

Visual

The torus semicircularis (part of tectum) receives which type of stimuli?

Auditory

What is the function of cranial nerves three and four in the tegmentum?

Eye movement

Which species have a well-developed mesencephalon?

Fish and amphibians

What are cerebral peduncles (mesencephalon)?

Groups of white matter bodies

What are the “four bodies” in the mesencephalon?

Corpora quadrigemina

What is the narrow channel for CSF in the mesencephalon?

Cerebral aqueduct

What are the black-colored cell bodies in the mesencephalon?

Substantia nigra

What disease is caused by an absence of substantia nigra?

Parkinson’s

What are the names of the bodies that make up the corpora quadrigemina?

Superior and inferior colliculus

What is the function of the thalamus?

Relays sensory/motor info

What kind of function do the hypothalamus and pituitary gland have?

Endocrine

What is the pineal gland involved in?

Circadian rhythm

What are the mammillary bodies involved in?

Emotion, behavior, memory

What is the advantage of a cerebrum with more folds?

Increase surface area to fit more nerve bodies

What are the sulci of the brain?

Grooves on brain surface

What are the gyri of the brain?

Ridges/folds on cerebral surface

What is a proprioceptor?

Sensory receptor that detects position and movement

What are the general functions of the forebrain among species?

Olfaction, behaviors, muscle control

What are the general functions of the midbrain among species?

Vision, lateral line systems

What is grey matter?

Cell bodies of neurons

Where is grey matter found?

Outermost area of brain/innermost area of spinal cord

Where is white matter found?

Innermost area of brain/outermost area of spinal cord

What is white matter?

Myelinated axons

Which part of the grey matter receives incoming afferent sensory information and sends to the brain?

Dorsal horn

Which part of the grey matter controls motor neurons?

Ventral horn

Look at the neuron

I looked at the neuron