A&P1, CH 12-15, Exam 4

Brain stem

Collectively the midbrain, pons, and medulla of the brain.

Glaucoma

Condition in which intraocular pressure increases to levels that cause compression of the retina and optic nerve; results in blindness unless detected early. The eventual result is blindness unless the condition is detected and treated early. Unfortunately, many forms of _______steal sight so slowly and painlessly that people do not realize they have a problem until the damage is done. Late signs include seeing halos around lights and blurred vision.

Thalamus

Consists of bilateral egg-shaped nuclei, which form the superolateral walls of the third ventricle. A mass of gray matter in the diencephalon of the brain. Meaning "inner room," which well describes this deep, well-hidden brain region that makes up 80% of the diencephalon. Is the relay station for information coming into the cerebral cortex Inputs that help regulate emotion and visceral function from the hypothalamus (via the anterior nuclei) Instructions that help direct the activity of the motor cortices from the cerebellum and basal nuclei (via the ventral lateral and ventral anterior nuclei, respectively) Inputs for memory or sensory integration that are projected to specific association cortices (via pulvinar, lateral dorsal, and lateral posterior nuclei) In summary, it plays a key role in mediating sensation, motor activities, cortical arousal, learning, and memory. It is truly the gateway to the cerebral cortex.

Substantia Nigra

Dopamine is secreted by the ___________ and is deficient in Parkinson disease.

Stress

Anything that causes the body to respond to an event that causes the body's natural fight-or-flight response.

Meninges

Are three connective tissue membranes that lie just external to the CNS organs. It's Functions: Cover and protect the CNS Protect blood vessels and enclose venous sinuses Contain cerebrospinal fluid Form partitions in the skull

Cerebellum

Brain region most involved in producing smooth, coordinated skeletal muscle activity. Regulates and coordinates movement, posture, balance and learning movement. The cauliflower-like, "small-Brain"

Receptor Types

Chemoreceptors (chemicals), nociceptors (pain), thermoreceptors (temp.), mechanoreceptors (mechanical touch pressure), and photoreceptors (light/eyes).

Dermatome map

Diagram of the areas of skin innervated by each spinal nerve. In patients with spinal cord injuries, you can pinpoint the damaged nerves and the injured region of the spinal cord by determining which dermatomes are affected.

Meninges Layers

From external to internal, the meninges are the Dura mater, Arachnoid mater, and Pia mater

Reticular Formation

Functional system that spans the brain stem; involved in regulating sensory input to the cerebral cortex, cortical arousal, and control of motor behavior. It is composed of loosely clustered neurons in what is otherwise white matter. maintains alert wakefulness of the cerebral cortex.

Central Sulcus

Lies in the frontal plane, separates the frontal lobe from the parietal lobe

Epithalamus

Most dorsal portion of the diencephalon; forms the roof of the third ventricle with the pineal gland extending from its posterior border.

Inner (Retina) Tunic

Neural tunic of the eyeball; the innermost of the three tunics of the eye; contains photoreceptors (rods, cones) in the deepest layer, bipolar neurons, amacrine cells and horizontal cells in the middle layer, and ganglion cells in the superficial layer.

Cerebrospinal Fluid (CSF)

Plasmalike fluid that fills the cavities of the CNS and surrounds the CNS externally; protects the brain and spinal cord.

Midbrain

Region of the brain stem between the diencephalon and the pons.

Hypothalamus

Region of the diencephalon forming the floor of the third ventricle of the brain. Caps the brain stem and forms the inferolateral walls of the third ventricle. Despite its small size, is the main visceral control center of the body and is vitally important to overall body homeostasis. Few tissues in the body escape its influence. Its chief homeostatic roles are to: Control the autonomic nervous system Initiate physical responses to emotions Regulate body temperature Regulate food intake Regulate water balance and thirst Regulate sleep-wake cycles Control endocrine system function

Photoreceptors

Specialized receptor cell that respond to light energy; rods and cones.

Basal Ganglia

Specific gray matter areas located deep within the white matter of the cerebral hemispheres. Subcortical motor centers Help control skeletal muscle movements Because a nucleus is a collection of neuron cell bodies within the CNS, the term basal nuclei is technically correct.

sympathetic

The ________________ division of the ANS functions mainly to prepare the body for energy-expending, stressful situations.

Cerebrum

The cerebral hemispheres (including the cerebral cortex, white matter, and basal nuclei). Is the largest part of the human brain, associated with higher brain function such as thought and action. Determining Intelligence Determining Personality Thinking Perceiving Producing and Understanding Language Interpretation of Sensory Impulses Motor Function Planning and Organization Touch Sensation

Corpus Collosum

The largest commissure, means "thickened body", which lies superior to the lateral ventricles, deep within the longitudinal fissure. neural bridge that connects the two hemispheres, located centrally.

Fibrous Tunic

The outermost coat of the eyeball consisting of dense collagenous tissue and divided into an anterior transparent cornea and a posterior opaque (white) sclera; this layer provides support, protection and determines the shape of the eye.

Eye Tunics

The three coats which form the wall of the eyeball, one inside the other, the outer fibrous, the middle vascular, and the inner sensory layers/coats/tunics.

Pineal Gland

The tiny, pinecone-shaped. A hormone-secreting part of the diencephalon of the brain thought to be involved in setting the biological clock and influencing reproductive function. Indirectly receives input from the visual pathways (retina → suprachiasmatic nucleus of hypothalamus → superior cervical ganglion →______) concerning the intensity and duration of daylight.

Arachnoid

Weblike; specifically, the weblike arachnoid mater, the middle layer of the three meninges.

External Ear

consists of the auricle and the external acoustic meatus. The auricle, or pinna, is what most people call the ear—the shell-shaped projection surrounding the opening of the external acoustic meatus. The auricle is composed of elastic cartilage covered with thin skin and an occasional hair. Its rim, the helix, is somewhat thicker, and its fleshy, dangling lobule ("earlobe") lacks supporting cartilage. The function of the auricle is to funnel sound waves into the external acoustic meatus.

Parts of the Ear

external, middle, internal.

Presbyopia

farsightedness caused by loss of elasticity of the lens of the eye, occurring typically in middle and old age.

Transverse Cerebral Fissure

separates the cerebral hemispheres from the cerebellum below

The consequence of sensory nerve fibers crossing over is that

the right hemisphere of the cerebrum receives sensory impulses originating on the left side of the body and vice versa

Myopia

A condition in which visual images are focused in front of rather than on the retina; nearsightedness.occurs when distant objects focus in front of the retina, rather than on it. Typically results from an eyeball that is too long.

Medulla Oblongata

Inferiormost part of the brain stem. It blends imperceptibly into the spinal cord at the level of the foramen magnum of the skull. The small size of the medulla belies its crucial role as an autonomic reflex center involved in maintaining homeostasis. The medulla contains these important functional groups of visceral motor nuclei: Cardiovascular center Respiratory centers Various other centers

Dura mater

Outermost and toughest of the three membranes (meninges) covering the brain and spinal cord. Is leathery. Meaning "tough mother," is the strongest meninx. Where it surrounds the brain, it is a two-layered sheet of fibrous connective tissue

Cerebrospinal fluid (CSF)

Plasmalike fluid that fills the cavities of the CNS and surrounds the CNS externally; protects the brain and spinal cord. found in and around the brain and spinal cord, forms a liquid cushion that gives buoyancy to CNS structures. By floating the jellylike brain, the CSF effectively reduces brain weight by 97% and prevents the delicate brain from crushing under its own weight. CSF also protects the brain and spinal cord from blows and other trauma. Additionally, although the brain has a rich blood supply, CSF helps nourish the brain, and there is some evidence that it carries chemical signals (such as hormones and sleep- and appetite-inducing molecules) from one part of the brain to another.

Meninges

Protective coverings of the central nervous system; from the most external to the most internal, the dura mater, arachnoid mater, and pia mater.

Proprioceptor

Receptor located in a joint, muscle, or tendon; concerned with locomotion, posture, and muscle tone. constantly advise the brain of our body movements by monitoring how much the organs containing these receptors are stretched. (propria = one's own)

Mechanoreceptor

Receptor sensitive to mechanical pressure such as touch, sound, or exerted by muscle contraction.

Thermoreceptors

Receptor sensitive to temperature changes.

Chemoreceptor

Receptor sensitive to various chemicals in solution.

Diencephalon

That part of the forebrain between the cerebral hemispheres and the midbrain including the thalamus, the epithalamus, and the hypothalamus.

Vascular Tunic

The middle coat of the eyeball consisting of highly vascular and heavily pigmented connective tissue consisting of a posterior choroid layer and an anterior ciliary body and the iris.

Cerebral Cortex

The outer gray matter region of the cerebral hemispheres. Is the "executive suite" of the nervous system, where our conscious mind is found. It enables us to be aware of ourselves and our sensations, to communicate, remember, understand, and initiate voluntary movements. Is composed of gray matter: neuron cell bodies, dendrites, associated glia and blood vessels, but no fiber tracts. It contains billions of neurons arranged in six layers. Although only 2-4 mm (about 1/8 inch) thick, it accounts for roughly 40% of total brain mass. Its many convolutions effectively triple its surface area.

Cerebrovascular accident (CVA)

The single most common nervous system disorder and the third leading cause of death in North America, also called stroke. Occur when blood circulation to a brain area is blocked and brain tissue dies of ischemia, a reduction of blood supply that impairs the delivery of oxygen and nutrients. The most common cause of CVA is a blood clot that blocks a cerebral artery.

Astigmatism

Unequal curvatures in different parts of the cornea or lens also lead to blurry images. Special cylindrically ground lenses or laser procedures are used to correct this problem.

Internal Ear

is also called the labyrinth ("maze") because of its complicated shape. It lies deep in the temporal bone behind the eye socket and provides a secure site for all of the delicate receptor machinery.

Longitudinal Fissure

is the deep groove that separates the two hemispheres of the vertebrate brain. The falx cerebri, a dural brain covering, lies within the medial ____________.

Pia Mater

meaning "gentle mother," is composed of delicate connective tissue and richly invested with tiny blood vessels. It is the only meninx that clings tightly to the brain like plastic wrap, following its every convolution. Small arteries entering the brain tissue carry ragged sheaths of this inward with them for short distances.

Hyperopia

or farsightedness, occurs when the parallel light rays from distant objects focus behind the retina. A condition in which visual images are routinely focused behind rather than on the retina; commonly known as farsightedness. ______ individuals can see distant objects because their ciliary muscles contract almost continuously to increase the light-bending power of the lens, which moves the focal point forward onto the retina. Usually results from an eyeball that is too short.

Middle Ear

or tympanic cavity, is a small, air-filled, mucosa-lined cavity in the petrous part of the temporal bone. It is flanked laterally by the eardrum and medially by a bony wall with two openings, the superior oval window and the inferior round window. The mastoid antrum, a canal in the posterior wall of the tympanic cavity, allows it to communicate with mastoid air cells housed in the mastoid process.

Lateral Sulcus

outlines the flaplike temporal lobe and separates it from the parietal and frontal lobes.