A&P II - Labex 1 (needs to be redone)

Question 1

Cerebrum

Answer 1

The cerebrum is a large part of the brain containing the cerebral cortex (of the two cerebral hemispheres), located superiorly and anteriorly in relation to the brainstem. The cerebrum is divided into four regions called lobes that control senses, thoughts, and movements. The four lobes are the occipital, temporal, frontal, and parietal lobes.

Question 2

Gyri/Gyrus

Answer 2

A gyrus (pl. gyri) is a ridge on the cerebral cortex. It is generally surrounded by one or more sulci. Gyri and sulci create the folded appearance of the brain in humans and other mammals. The gyri are part of a system of folds and ridges that create a larger surface area for the human brain. Gyri are unique structures that have an important evolutionary function; they increase the surface area of the brain up to an impressive 2000 centimeters squared.

Question 3

Sulci/Sulcus

Answer 3

Sulci, the grooves, and gyri, the folds or ridges make up the folded surface of the cerebral cortex. Larger or deeper sulci are termed fissures. The folded cortex creates a larger surface area for the brain. When looking at the human brain, two-thirds of the surface are hidden in the grooves. The sulci and fissures are both grooves in the cortex but they are differentiated by size. A sulcus is a shallower groove that surrounds a gyrus.

Question 4

Central Sulcus

Answer 4

The central sulcus is a part of your brain which stretches from the cerebral longitudinal fissures to the area close to the lateral sulcus of Sylvia’s fissure. It is seen as a fold or a deep groove which separates the convulsions on the surface of the brain.

Question 5

Longitudinal Fissure

Answer 5

The longitudinal fissure (or cerebral fissure, medial longitudinal fissure, or interhemispheric fissure) is the deep groove that separates the two hemispheres of the vertebrate brain. The medial surfaces of the two hemispheres are as similarly convoluted by gyri and sulci as is the outer surface of the brain.

Question 6

Frontal lobe

Answer 6

The frontal lobe, located at the front of the brain, is the largest of the four major lobes of the cerebral cortex in the mammalian brain. The frontal lobe is the part of the brain that controls important cognitive skills in humans, such as emotional expression, problem solving, memory, language, judgment, and sexual behavior. It is, in essence, the “control panel” of our personality and our ability to communicate.

Question 7

Precentral Gyrus

Answer 7

The precentral gyrus, which may also be called the primary motor area or, most commonly, the motor strip is immediately anterior to the central sulcus. It controls the voluntary movements of skeletal muscles. The precentral gyrus is a vertically oriented, cerebral convolution located immediately anterior to, and running parallel with, the central sulcus.

Question 8

Parietal Lobe

Answer 8

The parietal lobes can be divided into two functional regions. One involves sensation and perception and the other is concerned with integrating sensory input, primarily with the visual system. As a part of the cortex, it has a lot of responsibilities and has to be able to process sensory information within seconds. The parietal lobe is where information such as taste, temperature and touch are integrated, or processed.

Question 9

Parietal/Occipital Sulcus

Answer 9

The parieto-occipital sulcus (or parietooccipital fissure) is a deep furrow, anterior to the cuneus, that separates the occipital and the parietal lobes. Only a a small part (the lateral part) of the parieto-occipital sulcus is seen on the lateral surface of the hemisphere, its chief part (the medial part) being on the medial surface.

Question 10

Post Central Sulcus

Answer 10

The postcentral sulcus of the parietal lobe lies parallel to, and behind, the central sulcus in the human brain. The postcentral sulcus divides the postcentral gyrus from the remainder of the parietal lobe.

Question 11

Occipital Lobe

Answer 11

The occipital lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The occipital lobe is the visual processing center of the mammalian brain. The occipital lobe is the seat of most of the brain’s visual cortex, allowing you not only to see and process stimuli from the external world, but also to assign meaning to and remember visual perceptions. Located just under the parietal lobe and above the temporal lobe, the occipital lobe is the brain’s smallest lobe.

Question 12

Temporal Lobe

Answer 12

The temporal lobe is one of the four major lobes of the cerebral cortex located beneath the lateral fissure on both cerebral hemispheres of the mammalian brain. The lobe of the cerebral hemisphere located down on the side just forward of the occipital lobe. The temporal lobe contains the auditory cortex which is responsible for hearing. The Temporal Lobe mainly revolves around hearing and selective listening. It receives sensory information such as sounds and speech from the ears. It is also key to being able to comprehend, or understand meaningful speech.

Question 13

Insula

Answer 13

The insula is a small region of the cerebral cortex located deep within the lateral sulcus, which is a large fissure that separates the frontal and parietal lobes from the temporal lobe. The insulae are believed to be involved in consciousness and play a role in diverse functions usually linked to emotion or the regulation of the body’s homeostasis. These functions include compassion and empathy, perception, motor control, self-awareness, cognitive functioning, and interpersonal experience. In relation to these, it is involved in psychopathology.

Question 14

Cerebellum

Answer 14

The cerebellum is a major feature of the hindbrain of all vertebrates. Although usually smaller than the cerebrum, in some animals such as the mormyrid fishes it may be as large as or even larger. In humans, the cerebellum plays an important role in motor control, and it may also be involved in some cognitive functions such as attention and language as well as in regulating fear and pleasure responses, but its movement-related functions are the most solidly established.

Question 15

Posterior Cranial Fossa

Answer 15

The posterior cranial fossa is part of the cranial cavity, located between the foramen magnum and tentorium cerebelli. It contains the brainstem and cerebellum. This is the most inferior of the fossae. It houses the cerebellum, medulla and pons. Anteriorly it extends to the apex of the petrous temporal. Posteriorly it is enclosed by the occipital bone. Laterally portions of the squamous temporal and mastoid part of the temporal bone form its walls.

Question 16

Vermis

Answer 16

The cerebellar vermis is located in the medial, cortico-nuclear zone of the cerebellum, which resides in the posterior fossa of the cranium. The primary fissure in the vermis curves ventrolaterally to the superior surface of the cerebellum, dividing it into anterior and posterior lobes. Functionally, the vermis is associated with bodily posture and locomotion. The vermis is included within the spinocerebellum and receives somatic sensory input from the head and proximal body parts via ascending spinal pathways.

Question 17

Folia

Answer 17

A folium is a wrinkle (gyrus) on the surface of the cerebellum. The cortex (skin or rind) of a folium consists of three layers of cells—the top molecular layer, the Purkinje layer, and the bottom granular layer—and this cortex covers deeper white matter (interconnecting fibers).

Question 18

Sulci

Answer 18

Sulci, the grooves, and gyri, the folds or ridges make up the folded surface of the cerebral cortex. Larger or deeper sulci are termed fissures, and in many cases the two terms are interchangeable. The folded cortex creates a larger surface area for the brain in humans and other mammals

Question 19

Arbor Vitae (White Matter)

Answer 19

The arbor vitae is the cerebellar white matter, so called for its branched, tree-like appearance. In some ways it more resembles a fern and is present in both cerebellar hemispheres.[1] It brings sensory and motor information to and from the cerebellum. The arbor vitae is located deep in the cerebellum. Situated within the arbor vitae are the deep cerebellar nuclei; the dentate, globose, emboliform and the fastigial nuclei.

Question 20

Brain Stem

Answer 20

The brainstem (or brain stem) is the posterior part of the brain, adjoining and structurally continuous with the spinal cord. In the human brain the brainstem includes the midbrain, the pons, and the medulla oblongata. Sometimes the diencephalon, the caudal part of the forebrain, is included. The brainstem provides the main motor and sensory innervation to the face and neck via the cranial nerves.

Question 21

Diencephelon

Answer 21

The diencephalon of the brain consists of structures that are lateral to the third ventricle, and includes the thalamus, the hypothalamus, the epithalamus and the subthalamus. The diencephalon is one of the main vesicles of the brain formed during embryogenesis.

Question 22

Thalamus

Answer 22

The thalamus is a small structure within the brain located just above the brain stem between the cerebral cortex and the midbrain and has extensive nerve connections to both. The main function of the thalamus is to relay motor and sensory signals to the cerebral cortex.

Question 23

Hypothalamus

Answer 23

The hypothalamus is a portion of the brain that contains a number of small nuclei with a variety of functions. One of the most important functions of the hypothalamus is to link the nervous system to the endocrine system via the pituitary gland (hypophysis). The hypothalamus is located below the thalamus and is part of the limbic system. In the terminology of neuroanatomy, it forms the ventral part of the diencephalon. All vertebrate brains contain a hypothalamus. In humans, it is the size of an almond.

Question 24

Midbrain

Answer 24

The midbrain or mesencephalon is a portion of the central nervous system associated with vision, hearing, motor control, sleep/wake, arousal (alertness), and temperature regulation. The midbrain comprises the tectum, tegmentum, the cerebral aqueduct, and the cerebral peduncles, as well as several nuclei and fasciculi.

Question 25

Pons

Answer 25

The pons is part of the brainstem, and in humans and other bipeds lies inferior to the midbrain, superior to the medulla oblongata and anterior to the cerebellum. It helps relay messages from the cortex and the cerebellum. The pons contains nuclei that relay signals from the forebrain to the cerebellum, along with nuclei that deal primarily with sleep, respiration, swallowing, bladder control, hearing, equilibrium, taste, eye movement, facial expressions, facial sensation, and posture.

Question 26

Medulla Oblongata

Answer 26

The medulla oblongata (or medulla) is located in the brainstem, anterior and partially inferior to the cerebellum. It is a cone-shaped neuronal mass responsible for autonomic (involuntary) functions ranging from vomiting to sneezing. The medulla contains the cardiac, respiratory, vomiting and vasomotor centers and therefore deals with the autonomic functions of breathing, heart rate and blood pressure.

Question 27

Cranial Nerves

Answer 27

Cranial nerves are the nerves that emerge directly from the brain (including the brainstem), in contrast to spinal nerves (which emerge from segments of the spinal cord). 10 of 12 of the cranial nerves originate in the brainstem. Cranial nerves relay information between the brain and parts of the body, primarily to and from regions of the head and neck.

Question 28

Olfactory Nerve (Cranial Nerve I)

Answer 28

The olfactory nerve is typically considered the first cranial nerve, or simply CN I, that contains sensory nerve fibers relating to smell. The afferent nerve fibers of the olfactory receptor neurons, transmit nerve impulses about odors to the central nervous system, where they are perceived by the sense of smell (olfaction).

Question 29

Optic Nerve (Cranial Nerve II)

Answer 29

The optic nerve, also known as cranial nerve II, is a paired nerve that transmits visual information from the retina to the brain. In humans, the optic nerve is derived from optic stalks during the seventh week of development and is composed of retinal ganglion cell axons and glial cells. It extends from the optic disc to the optic chiasma and continues as the optic tract to the lateral geniculate nucleus, pretectal nuclei, and superior colliculus.

Question 30

Occulomotor Nerve (Cranial Nerve III)

Answer 30

The oculomotor nerve is the third cranial nerve. It enters the orbit via the superior orbital fissure and innervates muscles that enable most movements of the eye and that raise the eyelid. The nerve also contains fibers that innervate the muscles that enable pupillary constriction and accommodation (ability to focus on near objects as in reading).

Question 31

Trochlear Nerve (Cranial Nerve IV)

Answer 31

The trochlear nerve, also called the fourth cranial nerve or cranial nerve IV, is a motor nerve (a somatic efferent nerve) that innervates only a single muscle: the superior oblique muscle of the eye, which operates through the pulley-like trochlea. The trochlear nerve is unique among the cranial nerves in several respects: the smallest nerve in terms of the number of axons it contains, has the greatest intracranial length, the only cranial nerve that exits from the dorsal (rear) aspect of the brainstem.

Question 32

Trigeminal Nerve (Cranial Nerve V)

Answer 32

The trigeminal nerve is the fifth cranial nerve located within the brain, and is primarily responsible for transmitting sensations from the face to the brain. It is composed of three branches: the ophthalmic, maxillary, and mandibular. Responsible for sensation in the face and motor functions such as biting and chewing; it is the largest of the cranial nerves.

Question 33

Opthalmic Branch

Answer 33

The ophthalmic nerve (CN V: V1) is one of the three branches of the trigeminal nerve, the fifth cranial nerve. It carries sensory information from the face/scalp and sympathetic fibers for pupil dilation in the long ciliary branch of the nasociliary nerve.

Question 34

Maxillary Branch

Answer 34

Maxillary nerve. Alveolar branches of superior maxillary nerve and pterygopalatine ganglion. Distribution of the maxillary and mandibular nerves, and the submaxillary ganglion. The maxillary nerve (CN V2) is one of the three branches or divisions of the trigeminal nerve, the fifth (V) cranial nerve.

Question 35

Mandibular Branch

Answer 35

The mandibular nerve (V3) is the largest of the three divisions of the trigeminal nerve, the fifth cranial nerve (CN V). The marginal mandibular branch of the facial nerve passes forward beneath the platysma and depressor anguli oris, supplying the muscles of the lower lip and chin, and communicating with the mental branch of the inferior alveolar nerve. The nerve then divides into a small anterior and large posterior trunk.

Question 36

Abducens Nerve (Cranial Nerve VI)

Answer 36

The abducens nerve is a nerve that controls the movement of the lateral rectus muscle in humans, responsible for outward gaze. It is also known as the abducent nerve, the sixth cranial nerve. It is a somatic efferent nerve. The abducens nerve leaves the brainstem at the junction of the pons and the medulla, medial to the facial nerve. It runs upwards and forwards form this position to reach the eye.

Question 37

Facial Nerve (VII)

Answer 37

The facial nerve is the seventh cranial nerve, or simply cranial nerve VII. It emerges from the brainstem between the pons and the medulla, controls the muscles of facial expression, and functions in the conveyance of taste sensations from the anterior two-thirds of the tongue and oral cavity.

Question 38

Vestibulocochlear Nerve (Cranial Nerve VIII)

Answer 38

The vestibulocochlear nerve (auditory vestibular nerve), known as the eighth cranial nerve, transmits sound and equilibrium (balance) information from the inner ear to the brain. The vestibulocochlear nerve consists mostly of bipolar neurons and splits into two large divisions: the cochlear nerve and the vestibular nerve.

Question 39

Glossopharyngeal Nerve (IX)

Answer 39

The glossopharyngeal nerve, known as the ninth cranial nerve, is a mixed nerve that carries afferent sensory and efferent motor information. It exits the brainstem out from the sides of the upper medulla, just rostral (closer to the nose) to the vagus nerve.

Question 40

Vagus Nerve (X)

Answer 40

Vagus nerve, also called X cranial nerve or 10th cranial nerve, longest and most complex of the cranial nerves. The vagus nerve runs from the brain through the face and thorax to the abdomen. It is a mixed nerve that contains parasympathetic fibres. It contains motor and sensory fibers and, because it passes through the neck and thorax to the abdomen, has the widest distribution in the body.

Question 41

Accessory Nerve (XI)

Answer 41

The accessory nerve is a cranial nerve that supplies the sternocleidomastoid and trapezius muscles. The spinal accessory nerve originates from neuronal cell bodies located in the cervical spinal cord and caudal medulla. It is the eleventh cranial nerve (CN XI) and is composed of two parts, the cranial part and the spinal part.

Question 42

Hypoglossal Nerve (XII)

Answer 42

The hypoglossal nerve is the twelfth cranial nerve, and innervates all the extrinsic and intrinsic muscles of the tongue. The nerve has a purely somatic motor function, innervating the majority of the muscles of the tongue. The path of the nerve starts in the hypoglossal nucleus of the brainstem and then travels between the carotid artery and jugular vein to end up on the underside of the tongue.

Question 43

General Anatomy

Answer 43

The study of the structure and composition of the body as well as of its tissues and fluids. Deals with the way the parts of humans, from molecules to bones, interact to form a functional unit.

Question 44

Cranium

Answer 44

The top portion of the skull, which protects the brain. The cranium includes the frontal, parietal, occipital, temporal, sphenoid, and ethmoid bones. The top portion of the skull, which protects the brain.

Question 45

Meninges

Answer 45

The meninges are three layers of protective tissue called the dura mater, arachnoid mater, and pia mater that surround the neuraxis. The meninges of the brain and spinal cord are continuous, being linked through the magnum foramen. The primary function of the meninges and of the cerebrospinal fluid is to protect the central nervous system.

Question 46

Dura Mater

Answer 46

Dura mater, or dura, is a thick membrane that is the outermost of the three layers of the meninges that surround the brain and spinal cord. It is derived from mesoderm. The other two meningeal layers are the arachnoid mater and the pia mater.

Question 47

Arachnoid Mater

Answer 47

The arachnoid mater is the middle of three layers that make up the meninges, or membranes, that surround the spinal cord and brain. The dura mater is the outermost layer of the meninges. It is interposed between the two other meninges, the more superficial and much thicker dura mater and the deeper pia mater, from which it is separated by the subarachnoid space. The delicate arachnoid layer is attached to the inside of the dura and surrounds the brain and spinal cord.

Question 48

Pia Mater

Answer 48

The middle layer is the arachnoid mater, which is followed by a layer of cerebrospinal fluid. The pia mater is the innermost layer of the meninges and attaches directly to the brain and spinal cord. It is a very thin membrane composed of fibrous tissue covered on its outer surface by a sheet of flat cells thought to be impermeable to fluid.

Question 49

Ventricles

Answer 49

The ventricles of the brain are a communicating network of cavities filled with cerebrospinal fluid (CSF) and located within the brain parenchyma. The ventricular system is composed of 2 lateral ventricles, the third ventricle, the cerebral aqueduct, and the fourth ventricle

Question 50

Cerebrospinal Fluid

Answer 50

Cerebrospinal fluid is a clear, colorless body fluid found in the brain and spinal cord. It is produced in the choroid plexuses of the ventricles of the brain, and absorbed in the arachnoid granulations. The primary function of CSF is to cushion the brain within the skull and serve as a shock absorber for the central nervous system. Cerebrospinal fluid (CSF) is a clear, colorless liquid that surrounds and protects the CNS. It bathes the brain and spine in nutrients and eliminates waste products. It also cushions them to help prevent injury in the event of trauma.