Lab 10 - CNS

nuerons

specialized cells of the nervous system

• electrical signals cause them to release chemical messengers that are sensed by other cells across a synapse

soma

cell body of the neuron

• contains nucleus and all the cytoplasm of the cell

• attached to one or more dendrites and one axon

• contains specialized rough ER (nissl bodies) that produce proteins for nerve regeneration and growth

nissl bodies

the primary site for making proteins and enzymes that the neuron needs to grow, maintain itself, and repair damage; help manufacture the proteins and components needed to create neurotransmitters for sending signals across synapses

• made of rough ER, ribosomes, and RNA

dendrites

short, highly branched extensions that send singles towards the cell body

axon

a long, thin fiber of a neuron that sends electrical and chemical signals away from the cell body

axon hillock

the specialized, cone-shaped region of a neuron's cell body (soma) where the axon originates

presynaptic terminals

specialized bulb-like ending of an axon that sends chemical or electrical signals to a neighboring neuron, muscle, or gland cell

nodes of ranvier

small, regularly spaced gaps in the myelin sheath along the axon of a myelinated nerve cell

• increases impulse conduction speed

white matter

contains axons surrounded by fat (myelin sheath)

• gives a lighter color

• acts as insulation to help axons conduct signals faster

• includes tracts that ascend and descend through the brainstem and spinal cord

grey matter

contains neuron cell bodies

• no myelin

• also includes some unmyelinated axons

myelin

a protective, fatty-protein layer that wraps around the axons of neurons

central nervous system

brain and spinal cord

association neurons

a type of neuron that sits strictly within the central nervous system, connecting sensory and motor neurons

• usually relays from afferent to efferent

peripheral nervous system

cranial and spinal nerves

afferent (sensory) neurons

carry nerve impulses from sensory receptors in the body's tissues and organs toward the central nervous system (CNS)

• dendrites distal to CNS and axons proximal

efferent (motor) neurons

specialized neurons that carry signals away from the CNS to peripheral target organs, muscles, and glands

• dendrites proximal to CNS and axons distal

dura mater

the toughest and outermost of the three meningeal membranes

• consists of fibrous CT

• tightly connected to the periosteum inside the skull and to the brain

• forms venous sinuses

subdural space

space located between the inner surface of the dura mater and the outer surface of the arachnoid mater

• site of subdural hematomas

arachnoid mater

middle layer of the meninges

• cobweb - like

• avascular

subarachnoid space

fluid-filled interval located between the arachnoid mater and the pia mater

• contains circulating cerebrospinal fluid

arachnoid granulations

small, specialized protrusions of the arachnoid membrane that extend through the dura mater into the dural venous sinuses

• projects up into sagittal sinus, allows CSF to be drained into the circulatory system

pia mater

the delicate, innermost layer of the meninges

• adheres directly to brain

• cannot be seen with naked eye

meningitis

infection of the meninges and usually affects the pia or arachnoid layers

lateral ventricles

located in the lower medial portions of each cerebral hemisphere

septum pellucidum

a membrane that separates the lateral ventricles

choroid plexus

a specialized network of capillaries, loose connective tissue, and cuboidal epithelial cells that secrete CSF

third ventricle

a narrow, slit-like, fluid-filled cavity located on the midline in the area of the diencephalon

• not readily seen in sagittal section, but you can see the cerebral aqueduct leading away from this location

fourth ventricle

a diamond shaped, fluid-filled cavity located between the cerebellum and brainstem on the midline

• look for the cerebral aqueduct that connects the 3rd and 4th ventricles

frontal lobe

intellect, abstract reasoning, language, personality, and motor control

• the largest lobe of the human brain, located directly behind the forehead

motor cortex

a region in the posterior part of the frontal lobe of the brain that plans, selects, and executes voluntary muscle movements

sensory cortex

located in the parietal lobe; receives and processes information from the five senses and bodily receptors

parietal lobe

primary sensory cortex and association areas (helps you to know where you are)

• located near the top and back of the head, behind the frontal lobe

occipital lobe

primary visual cortex (visual processing center)

• located at the rearmost part of the brain directly underneath the occipital bone

temporal lobe

primary auditory cortex; hearing, language understanding, memory storage, and recognizing faces and objects

• located on each side of the head near the temples and ears

insula

balance and addictive behavior

• bridge between your body and your mind; it takes physical signals from inside your body and turns them into conscious feelings and awareness

• deeply folded inside the brain's lateral sulcus

diencephalon

connects the cerebrum (thinking and voluntary movement part) to the rest of the nervous system

• forms the wall of the 3rd ventricle

brainstem

controls the basic life functions you do without thinking

• stalk-like structure at the base of the brain that connects the cerebrum to the spinal cord

midbrain

pathway and processing center for vision, hearing, motor control, sleep-wake cycles, and temperature regulation

• the smallest, uppermost portion of the brainstem

pons

controls breathing, regulates sleep, manages facial movement and sensation, and relays sensory signals

• a major bridge and relay station between different parts of the brain and the spinal cord

• below the midbrain, but in front of the cerebellum

medulla

regulates breathing, heart rate, blood pressure, and manages reflexes

• connects brain to your spinal cord

broca’s area

a region in the frontal lobe of the brain's dominant hemisphere (usually the left) that is vital for speech production, language processing, and grammar

• damage to this causes difficulty with forming words

wernicke’s area

region of the brain involved in language processing; primary center for spoken and written language comprehension

• damage to this area causes “word soup”

  • severe difficulty understanding spoken / written language, empty speech (no sense), unawareness (do not understand something is wrong)

cerebellum

main job is to coordinate and smooth out physical movement; “little brain”

• a major structure located at the back of the skull, sitting directly beneath the occipital and temporal lobes of the cerebrum and behind the brainstem

arbor vitae

tree-like structure of white matter located inside the cerebellum

• acts as a highway to transmit sensory and motor signals to and from the rest of the brain

spinal cord

a cylindrical bundle of nervous tissue that runs from the base of the brainstem down the center of the back

• the cord is shorter than the column

cervical enlargement

upper limb innervation

• a thickened, oval-shaped region of the spinal cord spanning roughly from the C3 to T1

lumbar enlargement

a widened section of the spinal cord that processes signals for the lower half of the body

conus medullaris

nerve transmission and pelvic and lower limb control

• tapered, cone-shaped lower end of the spinal cord

cauda equina

sends and receives signals between the CNS and the lower body

• a bundle of spinal nerve roots and nerve branchlets originating from the lumbar and sacral levels inside the spinal canal

filum terminale

anchor and stabilize the lower end of the spinal cord to the coccyx, preventing excessive upward or vertical movement within the spinal canal

• delicate, thread-like strand of fibrous and pial tissue that extends inferiorly from the the conus medullaris