Lab Practical 4

Front 1

Astrocyte

Back 1

Neuroglial cell in the CNS; has many processes that makes it star-shaped; perivascular feet wrap around and cover neurons and blood vessels to keep neurons in place; guide neurons during development, control the composition of the chemical environment of the neurons by forming a blood-brain barrier.

Front 2

Oligodendrocytes

Back 2

Support CNS neurons and have processes that form myelin sheaths around axons to increase speed of nerve impulses.

Front 3

Microglia

Back 3

The phagocytes of the CNS that engulf debris, necrotic tissue, and invading bacteria or viruses.

Front 4

Ependymal cells

Back 4

line all four ventricles of the brain as well as the central canal of the spinal cord. these cells form CSF and their cilia move the CSF through the ventricles.

Front 5

Schwann cells

Back 5

flattened cells that wrap around the axons in the PNS. Many Schwann cells form the myelin sheath around one axon.

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Satellite cells

Back 6

have processes that are flattened and surround the sensory neuron cell bodies located in ganglia in the PNS. They give support to these neurons and regulate their chemical environment

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Multipolar neurons

Back 7

have numerous processes, with many dendrites and one axon. motor neurons and interneurons are multipolar and comprise most of the CNS neurons

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Bipolar neurons

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have 2 processes - 1 dendrite and 1 axon on either side of the cell body and are found in special senses like the retina of the eye, olfactory cells of the nose, and the inner ear.

Front 9

Unipolar neurons

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have only one process, an axon, leading to and from the neuron cell body. The dendrites are small and attach to the axon instead of the cell body. unipolar neurons are sensory neurons that bring sensory information from the skin, muscles, and organs to the spinal cord

Front 10

Functional classifications of neurons

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sensory (afferent neuron) - unipolar neuron that detects changes in the environment; the axon of the sensory neuron synapses with either a motor neuron or an interneuron
interneuron (association neuron) - multipolar neuron; comprises 90% of neurons in CNS; can synapse with more interneurons or with motor neuron
Motor (efferent) neuron - takes the impulse out of the spinal cord via a spinal nerve to an effector. structurally multipolar

Front 11

3 types of neuron synapses

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axoaxonic - axon to axon
axodendritic - axon to dendrite
axosomatic - axon to cell body

Front 12

Epidural space

Back 12

adipose tissue cushions the spinal cord and is found within the space between the vertebrae and the meninges known as the epidural space

Front 13

Spinal cord meninges

Back 13

dura mater - the out meninx, is tough, single-layered membrane that is deep to the epidural space and superficial to the spider web-like arachnoid mater
pia mater - the inner meninx is delicate and hugs the spinal cord

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Subarachnoid space

Back 14

located between the pia and arachnoid mater and contains CSF which also cushions the spinal cord

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brain stem

Back 15

comprised of three structures: the medulla oblongata, the pons, and the midbrain

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medulla oblongata

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located immediately superior to the spinal cord; most vital part of the brain because it houses the respiratory and cardiovascular control centers. the respiratory center controls the rate and depth of breathing and the cardiovascular center is responsible for the rate and force of heartbeat and blood pressure reflexes. other reflex centers in the medulla are for coughing, vomiting, and sneezing

Front 17

pons

Back 17

the pons is an expanded structure located superior to the medulla oblongata and anterior to the cerebellum, and has respiratory centers that assist the medulla oblongata in controlling breathing. the pons also relays information to the diencephalon and the cerebellum.

Front 18

midbrain

Back 18

a smaller area superior to the pons and inferior to the diencephalon, consisting of cerebral peduncles and the corpora quadrigemina. cerebral peduncles are white fibers that connect the upper and lower brain areas, and the corpora quadrigemina are composed of 2 superior colliculi, which have reflex centers involved in eye, hand, and neck movements with visual stimulation, whereas the inferior colliculi have reflex centers involved in auditory stimuli that result in head and trunk movements.

Front 19

cerebellum

Back 19

located inferior to the cerebrum and posterior to the medulla and pons; the cerebrum regulates posture and balance and, in addition, smooths and coordinates skilled skeletal muscle movements. the cerebellumm is connected to the brain stem by the superior, middle, and inferior cerebellar pedunlces.

Front 20

Features of the cerebellum

Back 20

there are 2 cerebellar hemispheres, with a central area, the vermis, connecting them. when cut in sagittal section, gray matter can be observed on the exterior, with deeper white matter called the arbor vitae appearing as branches of a tree. the outer layer of gray matter is called the cerebellar cortex. the cerebellar cortex has folds called folia.

Front 21

Diencephalon

Back 21

located in the brain's central area and has 3 main regions: the thalamus, the hypothalamus, and the epithalamus

Front 22

Thalamus

Back 22

composed of paired, egg-shaped bodies centrally located in the diencephalon and comprises approximately 80% of this structure. Each cerebral hemisphere contains half of the thalamus which is connected by a small bridge called the intermediate mass. the thalamus is the brain's "grand central relay station" and the secretary of the brain because it is the principal relay station for sensory fibers and some somatic motor fibers. sensory fibers that synapse in the thalamus are relayed to a particular area of the cerebral cortex to be interpreted, and other fibers relay messages to the somatic motor cortex. the thalamus also filters out unnecessary sensory information and is involved in consciousness, emotions, learning, and memory.

Front 23

Hypothalamus

Back 23

located below the thalamus and is quadrangular in shape; has important nuclei that control many body functions and homeostasis. some of the major functions include integrating and controlling pituitary gland and hormonal functions, autonomic functions, emotions and behavior, body temperature, eating, and drinking

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features of the hypothalamus

Back 24

infundibulum - a stalk that connects the pituitary gland to the hypothalamus
mammillary bodies - two small, round masses located just posteriot to the infundibulum, relay stations for smell and taste reflexes
optic chiasm - area where the optic nerves cross, anterior to the infundibulum
pituitary gland - looks like a large pea and is attached to the infundibulum. the hypothalamus controls the pituitary gland.

Front 25

epithalamus

Back 25

superior and posterior to the thalamus and includes the pineal gland, a small endocrine gland that secretes the hormone menatonin

Front 26

Cerebrum

Back 26

made up of the right and left cerebral hemispheres and is the largest and most complex division of the brain. the cerebrum is the center of higher mental processes such as intelligence, communication, learning and memory, reasoning, and emotions. in addition, it interprets sensory input and initiates skeletal muscle contraction

Front 27

Cerebral cortex

Back 27

the superficial gray matter on the exterior of the cerebrum composed of nerve cell bodies and dendrites. it integrates sensory information, motor output, and is also involved in emotions and intellectual processes

Front 28

basal ganglia

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areas of gray matter composed of paired nuclei that are found deep within each cerebral hemisphere. they control automatic skeletal muscle movement and are involved with the limbic system or emotional brain

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white matter

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lies deep to the outer cortex and is comprised mostly of myelinated axons that give it the white appearance; organized into 3 different fiber tracts: association fibers, commissural fibers, and ascending fibers.

Front 30

Corpus callosum

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a prominent commissural fiber tract that is readily observable in midsagittal sections of the brain, and connects the two cerebral hemispheres

Front 31

Internal capsule

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a large group of projection fibers that contain sensory and motor tracts that connect the cerebral cortex to the brain stem and spinal cord

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central sulcus

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shallow groove separating frontal lobe from parietal lobe

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precentral gyrus

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elevation located just anterior to the central sulcus

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postcentral gyrus

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elevation located just posterior to the central sulcus

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lateral cerebral sulcus

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shallow groove separating frontal and temporal lobes

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parieto-occipital sulcus

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shallow groove separating parietal and occipital lobes

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longitudinal fissure

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deep groove separating the 2 cerebral hemispheres at the midline

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transverse fissure

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deep groove separating the cerebrum from the cerebellum in the posterior/inferior part of the brain

Front 39

primary motor area

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located in the precentral gyrus of each frontal lobe; initiates impulses to skeletal muscles

Front 40

Broca's speech area

Back 40

motor area located superior to the lateral sulcus and anterior to the primary motor cortex, usually in the left hemisphere; initiates impulses that result in speech

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Primary somatosensory area

Back 41

sensory area located in the postcentral gyrus of each parietal lobe; receives nerve impulses for touch, proprioception, pain, and temperature

Front 42

Primary auditory area

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sensory area located in each temporal lobe across the lateral sulcus from the gustatory area; receives impulses when the auditory receptors of the ear are stimulated

Front 43

Primary gustatory area

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sensory area in each postcentral gyrus, just superior to the lateral sulcus; receives impulses when the taste buds are stimulated

Front 44

primary olfactory area

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sensory area located on the medial side of each temporal lobe; cannot be seen from the lateral view; receives impulses when the olfactory receptors of the nose are stimulated

Front 45

primary visual area

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sensory area in the posterior occipital lobe; receives impulses from the thalamus when the retina is stimulated

Front 46

Wernicke's area

Back 46

association area located in left temporal and parietal lobes; recognizes spoken words, translates words into thoughts, and possibly helps us sound out strange or new words

Front 47

somatosensory, visual, and auditory association areas

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larger areas adjacent to the corresponding sensory cortex; integrate sensory information from the sensory cortex with past experiences allowing us to identify objects by touch or to identify sound as music or speech

Front 48

Dura mater

Back 48

the first meninx located deep to the cranial bones; it is comprised of two layers: the periosteal layer, which is a tough membrane attached to the cranial bones, and the meningeal layer, which is exterior to the arachnoid mater. the two dural layers split to form the dural sinuses that eventually drain cranial blood into the jugular veins. the superior sagittal sinus, located superior to the longitudinal fissure, is one of the main dural sinuses. the double-layered dura mater extends deep into the longitudinal fissure forming the falx cerebri, into the transverse fissure forming the tentorium cerebelli, and between the cerebellar hemispheres forming the falx cerebelli.

Front 49

Arachnoid mater

Back 49

the 2nd meninx located deep to the dura mater. projections of the arachnoid mater into the dural sinuses are called arachnoid villi

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pia mater

Back 50

the thin, inner meninx. it hugs and overlays the cerebral cortex, following each gyrus and sulcus

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subarachnoid space

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located between the arachnoid and pia mater

Front 52

choroid plexus

Back 52

specialized, tiny blood vessels that produces CSF from blood plasma; located in the roof of all 4 ventricles

Front 53

Fibrous tunic

Back 53

outer layer of the eyeball composed of the cornea and sclera

Front 54

cornea

Back 54

the transparent anterior portion that covers the iris and pupil

Front 55

sclera

Back 55

the tough, white part of the eye that forms the majority of the eyeball

Front 56

vascular tunic

Back 56

middle layer of the eyeball composed of the iris, ciliary body, and choroid.

Front 57

iris

Back 57

the most anterior portion of the vascular tunic and contains pigmented cells. it is made of circular smooth muscle and controls the pupil size

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pupil

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the opening in the middle of the iris that allows light to enter the eyeball and changes size in response to the intensity of light

Front 59

ciliary body

Back 59

begins posterior to the iris at the junction of the cornea and sclera and consists of the ciliary muscle and ciliary processes
ciliary muscle - a circular smooth muscle that contracts to control the shape of the lens
ciliary processes - folds that protrude form the ciliary body toward the lens; they contain capillaries that secrete aqueous humor, the fluid in the anterior chamber of the eyeball

Front 60

suspensory ligaments

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thin fibers that attach to the lens to these processes

Front 61

choroid

Back 61

the most posterior part of the vascular tunic that lines most of the interior sclera. it contains many blood vessels that nourish the retina

Front 62

retina

Back 62

the inner coat that begins at the ora serrata, the serrated boundary between the ciliary muscle and the retina. the retina continues posteriorly, lining the interior of the choroid. the pigmented layer of the retina is the outer portion, and the neural layer is the inner portion that contains photoreceptors and associated neurons

Front 63

lens

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divides the interior of the eyeball into an anterior cavity and a vitreous chamber

Front 64

anterior cavity

Back 64

space between the cornea and the lens that is filled with watery aqueous humor. this cavity is subdivided into an anterior chamber (between the cornea and iris) and a posterior chamber (between the iris and lens)

Front 65

scleral venous sinus (canal of Schlemm)

Back 65

an opening found at the junction of the cornea and sclera that drains aqueous humor back into the bloodstream

Front 66

vitreous chamber

Back 66

large, posterior cavity located between the lens and the retina. this cavity is filled with a gel-like substance called the vitreous body (humor) that holds the retina flat against the choroid.

Front 67

5 components of a reflex arc

Back 67

sensory receptor, sensory neuron, integrating center, motor neuron, effector

Front 68

somatic reflexes

Back 68

result in skeletal muscle contraction
spinal reflexes: patellar refles, achilles reflex, flexor and crossed extensor reflexes, plantar reflex
cranial reflexes: corneal reflex, gag reflex

Front 69

autonomic reflexes

Back 69

result in cardiac/smooth muscle contraction/gland activity; includes pulillary light and consensual reflexes, ciliospinal reflex, salivary reflex

Front 70

association fibers, commissural fibers, projection fibers

Back 70

association fibers transmit nerve impulses within the same hemisphere, commissural fibers transmit nerve impulses between two hemispheres, and projection fibers are ascending and descending tracts that project nervous impulses from inferior to superior brain or vise versa