Module 4.1 Structure Of The Vertebrate Nervous System

Front 1

Dorsal

Back 1

Toward the back, away from the ventral (stomach) side. The top of the brain is considered dorsal because it has that position in four-legged animals

Front 2

Ventral

Back 2

Toward the stomach, away from the dorsal (back) side

Front 3

Anterior

Back 3

Toward the front end

Front 4

Posterior

Back 4

Toward the rear end

Front 5

Superior

Back 5

Above another part

Front 6

Inferior

Back 6

Below another part

Front 7

Lateral

Back 7

Toward the side, away from the midline

Front 8

Medial

Back 8

Toward the midline, away from the side

Front 9

Proximal

Back 9

Located close (approximate) to the point of origin or attachment

Front 10

Ipsilateral

Back 10

On the same side of the body (e.g., two parts on the left or two on the right)

Front 11

Contralateral

Back 11

On the opposite side of the body (one on the left and one on the right) or a structure or signal that originates on one side of the body and crosses to the other side

Front 12

Coronal plane

Back 12

A plane that shows brain structures as seen from the front. If you were to cut through the coronal plane you would bisect the head through the ears, creating a front half and a back half.

Front 13

Sagittal plane

Back 13

A plane that shows brain structures as seen from the side. If you were to cut through the sagittal plane, you would bisect the head through the nose and creating a left and a right half.

Front 14

Horizontal plane

Back 14

A plane that shows brain structures as seen from above. If you were to cut through the horizontal plane, you would bisect the head at the eyes, creating a top and a bottom half.

Front 15

Somatic Nervous System

Back 15

part of the Peripheral Nervous System which consists of the axons conveying sensory messages from the sense organs to the CNS and motor messages from the CNS to the muscles. Its cell bodies are located in the brain or the spinal cord, and their axons link to muscles. It controls voluntary muscles and conveys sensory information to the CNS

Front 16

Autonomic Nervous System

Back 16

another part of the PNS, this system controls internal organs such as the heart, intestines, and other organs. It monitors organ function not under conscious control and control involuntary muscles.

Front 17

Lamina

Back 17

a row or layer of cell bodies separated from other cell bodies by a layer of axons and dendrites

Front 18

Column

Back 18

a set of cells perpendicular to the surface of the cortex, with similar properties, opposite of lamina

Front 19

Tract

Back 19

A set of axons within the CNS, also known as a projection. If axons extend from cell bodies in structure A to synapses onto B, we say that the fibers "project" from A onto B

Front 20

Nerve

Back 20

A set of axons in the PNS, either from the CNS to a muscle or gland or from a sensory organ to the CNS

Front 21

corpus callosum

Back 21

a bundle of nerve fibers through which the left and right hemispheres of the brain communicate

Front 22

cerebral cortex

Back 22

* Thought
* Voluntary movement
* Language
* Reasoning
* Perception
Gray matter, is the outer layer of the brain

Front 23

gyrus

Back 23

bulge of cortex

Front 24

sulcus

Back 24

groove of cortex

Front 25

Cerebellum

Back 25

a large hindbrain structure with many deep folds.
* (fine) Movement
* Balance
* Posture

Front 26

brain stem

Back 26

* Breathing
* Heart Rate
* Blood Pressure

The brain stem is a general term for the area of the brain between the thalamus and spinal cord. Structures within the brain stem include the medulla, pons, pineal gland, superior and inferior colliculi, tectum, reticular formation and tegmentum. (midbrain, pons, medulla, pineal gland) Some of these areas are responsible for the most basic functions of life such as breathing, heart rate and blood pressure.

Front 27

Hypothalamus

Back 27

* Body Temperature
* Emotions
* Hunger
* Thirst
* Circadian Rhythms

Front 28

Thalamus

Back 28

* Sensory processing
* Movement

The thalamus receives sensory information and relays this information to the cerebral cortex. The cerebral cortex also sends information to the thalamus which then transmits this information to other areas of the brain and spinal cord.

Front 29

Limbic System

Back 29

* Emotions
* Memory

The limbic system (or the limbic areas) is a group of structures that includes the amygdala, the hippocampus, mammillary bodies and cingulate gyrus. These areas are important for controlling the emotional response to a given situation. The hippocampus is also important for memory.

Front 30

Hippocampus

Back 30

* Learning
* Memory

Front 31

Basal Ganglia

Back 31

* Movement

The basal ganglia are a group of structures, including the globus pallidus, caudate nucleus, subthalamic nucleus, putamen and substantia nigra, that are important in coordinating (slow) movement.

Front 32

Midbrain

Back 32

* Vision
* Audition
* Eye Movement
* Body Movement
The midbrain is the smallest region of the brain that acts as a sort of relay station for auditory and visual information.

The midbrain controls many important functions such as the visual and auditory systems as well as eye movement. Portions of the midbrain called the red nucleus and the substantia nigra are involved in the control of body movement. The darkly pigmented substantia nigra contains a large number of dopamine-producing neurons are located. The degeneration of neurons in the substantia nigra is associated with Parkinson’s disease.

The midbrain includes structures such as the superior and inferior colliculi and red nucleus. There are several other areas also in the midbrain.

Front 33

Sympathetic system

Back 33

Division of the Autonomic system. It mobilizes the body for fight or flight responses, increasing breathing and heart rate and decreasing digestive activity. It consists of chains of ganglia to the left and right of the spinal cord's central regions. These ganglia are connected by axons to the spinal cord. Sympathetic ganglia are closely linked and they often act as a single system. The sweat glands, adrenal glands, the muscles that constrict blood vessels, and the muscles that erect the hairs of the skin have only sympathetic, not parasympathetic responses.

Front 34

Parasympathetic system

Back 34

Division of the Autonomic system. It conserves energy and maintains homeostasis at a resting state. Unlike the ganglia in the sympathetic system, the parasympathetic ganglia are not arranged in a chain near the spinal cord. Instead the preganglionic neuron extends from the spinal cord to parasympathetic ganglia close to each internal organ; shorter postganglionic fibers then extend from the parasympathetic ganglia into the target organs. The parasympathetic nervous system's postganglionic axons release the neurotransmitter acetycholine. The sympathetic system uses norepinephrine. Because the two systems use different transmitters, certain drugs excite or inhibit one system or the other.

Front 35

Spinal cord

Back 35

Part of the CNS within the spinal column. The spinal cord communicates with all sense organs and muscles except those of the head. It is a segmented structure, and each segment has on each side a sensory nerve and a motor nerve.

Front 36

Bell-Magendie law

Back 36

One of the first discoveries about the functions of the nervous system, the entering dorsal roots carry sensory information into the spinal cord, and the exiting ventral roots carry motor information.

Front 37

Dorsal root ganglia

Back 37

the cell bodies of the sensory neurons are found in these clusters of neurons OUTSIDE the spinal cord. Cell bodies of motor neurons are INSIDE the spinal cord

Front 38

Gray matter

Back 38

unmyelinated axons found on the outside surface of the brain. Also found in the center of the spinal cord.

Front 39

white matter

Back 39

myelinated axons found surrounding the gray matter in the spinal cord. Many neurons of the spinal cord send axons from the gray matter in the spinal cord through the white matter.

Front 40

hindbrain

Back 40

One of three major divisions of the brain. It has three subdivisions: the rhombencephalon, metencephalon, and the myelencephalon. It consists of the medulla, pons, and cerebellum

Front 41

medulla

Back 41

a structure just above the spinal cord, which could be regarded as an enlarged extension of the spinal cord located in the skull. It controls vital reflexes such as breathing, heart rate, vomiting, salivation, coughing, and sneezing through the cranial nerves.

Front 42

cranial nerves

Back 42

nerves which control sensations from the head, muscle movements in the head, and much of the parasympathetic output to the organs. Some cranial nerves have both sensory and motor components; some have just one or the other. There are 12 pairs of cranial nerves, one of each pair on the right of the brain and one on the left of the brain. The nuclei of the cranial nerves are located in the medulla, pons, midbrain, and forebrain (see Figure 4.9)

Front 43

pons

Back 43

the term pons is Latin for "bridge," reflecting that many axons in the pons cross from one side of the brain to the other. This is the location where axons from each half of the brain cross to the opposite side of the spinal cord so that the left hemisphere controls the muscles of the right side of the body and the right hemisphere controls the left side. The medulla and the pons contain the reticular formation and the raphe system

Front 44

reticular formation

Back 44

A network of nerve pathways and nuclei throughout the brainstem, connecting motor nerves and sensory nerves to and from the spinal cord, the cerebellum, and the cerebrum. It is estimated that a single neuron in this network may have synapses with as many as 25,000 other neurons.
The reticular formation has descending and ascending portions. The descending portion is one of the several brain areas that controls the motor areas of the spinal cord. The ascending portion sends output to much of the cerebral cortex, selectively increasing arousal and attention in one area or another.
Function:
awaking/sleeping cycle
filtering incoming stimuli to discriminate irrelevant background stimuli

Front 45

raphe system

Back 45

sends axons to much of the forebrain, modifying the brain's readiness to respond to stimuli

Front 46

cerebellum

Back 46

a large hindbrain structure with many deep folds. It contributes to (fast) movement, balance, equilibrium, and coordination, but its functions extend beyond balance and coordination. People with damage to the cerebellum have trouble shifting their attention back and forth between auditory and visual stimuli. They also have difficulty with timing, especially sensory timing

Front 47

Myelencephalon (marrow-brain)

Back 47

hindbrain structure
Medulla – respiratory, vital life reflexes, heart rate, blood pressure, etc.
Reticular formation – involved in attention and arousal, it occurs in the first four subdivisions of the brain: myelencephalon, metencephalon, mesocephalon, diencephalon

Front 48

Metencephalon (afterbrain)

Back 48

hindbrain structure
Pons – relays sensory and motor info to and from the brain
Cerebellum – balance, coordination, fast movement, eye-hand coordination
parts of reticular formation

Front 49

Rhombencephalon (parallelogram-brain)

Back 49

hindbrain structure
Medulla, pons, cerebellum (metencephalon, myelencephalon, and reticular formation
* Attention and Sleep
* Autonomic Functions
* Complex Muscle Movement
* Conduction Pathway for Nerve Tracts
* Reflex Movement
* Simple Learning

Front 50

Midbrain (Mesocephalon)

Back 50

Tectum – Controls Auditory and Visual Responses, consists of superior colliculus and inferior colliculus
Superior colliculus – visual reflexes (i.e., change in light level). Superior is on top of the inferior colliculus
Inferior colliculus – auditory reflexes (i.e., changes in sound level)

Front 51

Diencephalon (between-brain)

Back 51

Thalamus – sends all sensory information to the cortex except for olfactory information. Olfactory information goes into the olfactory bulbs and then is distributed throughout the brain.
Hypothalamus – involved in homeostasis – maintaining optimal levels of the body, controls pituitary

Front 52

Telencephalon (end-brain)

Back 52

Basal ganglia – a group of structures which control discrete movements (movement involving feedback)
Hippocampus – involved in recent memories, storing
Cerebral cortex – the wrinkly outer surface of the brain, outside is unmyelinated fibers (gray)
Limbic system – not one, but many structures that have a common function which is the regulation of emotions.
Hypothalamus, thalamus, olfactory bulb, amygdala, hippocampus, mamillary body, and cingulate gyrus
Cingluate gyrus – specific function is aggression, rage, and memory
Mamillary body – associated with recent memories
Hippocampus – involved in recent memories
Amygdala – aggression, rage, memory
Olfactory bulbs – emotion and smell

Front 53

Prosencephalon (forward-brain)

Back 53

frontal lobe

Front 54

tectum

Back 54

roof of the midbrain

Front 55

superior colliculus

Back 55

swelling on the upper part of the tectum which is mainly important for vision

Front 56

inferior colliculus

Back 56

swelling on the lower part of the tectum which is mainly for hearing

Front 57

tegmentum

Back 57

the intermediate level of the midbrain. The tegmentum covers several other midbrain structures

Front 58

substantia nigra

Back 58

a midbrain structure which gives rise to dopamine-containing pathway that facilitates readiness for movement. It is part of the basal ganglia. The basal ganglia and cerebellum are large collections of nuclei that modify movement on a minute-to-minute basis. The output of the cerebellum is excitatory, while the basal ganglia are inhibitory.
* Controls Voluntary Movement
* Produces the Neurotransmitter Dopamine
* Regulates Mood

Front 59

forebrain

Back 59

the most anterior and most prominent part of the mammalian brain. It controls voluntary movement.

Front 60

limbic system

Back 60

a number of structures that form a border around the brainstem. They are particularly important for motivations and emotions. The structures are olfactory bulb, hypothalamus, hippocampus, amygdala, and cingulate gyrus.

Front 61

thalamus

Back 61

part of the diencephalon, along with the hypothalamus. The thalamus is a pair of structures in the center of the forebrain. The thalamus processes sensory information and sends it to the cerebral cortex (except for olfactory information). The cerebral cortex sends information back to the thalamus, prolonging and magnifying certain kinds of input at the expense of others, thereby focusing attention on particular stimuli

Front 62

hypothalamus

Back 62

a small area near the base of the brain just ventral to the thalamus. It has widespread connections with the rest of the forebrain and midbrain. Through nerves and hypothalamic hormones, the hypothalamus conveys messages to the pituitary gland, altering its release of hormones. Damage to any hypothalamic nucleus leads to abnormalities in motivated behaviors, such as feeding, drinking, temperature regulation, sexual behavior, fighting or activity level.

Front 63

pituitary gland

Back 63

the pituitary gland is an endocrine gland attached to the base of the hypothalamus by a stalk that contains neurons, blood vessels, and connective tissue. In response to messages from the hypothalamus, the pituitary synthesizes and releases hormones into the bloodstream, which carries them to other organs.

Front 64

basal ganglia

Back 64

a group of subcortical structures lateral to the thalamus, includes the caudate nucleus, the putamen, and globus pallidus. The basal ganglia have subdivisions that exchange information with different parts of the cerebral cortex. The connections are most abundant with the frontal areas of the cortex, which are responsible for planning sequences of behavior and for certain aspects of memory and emotional expression. In conditions such as Parkinson's disease and Huntington's disease, the basal ganglia deteriorate and the most prominent symptom is impaired movement, but people also show depression and deficits of memory, reasoning, and attention

Front 65

nucleus basalis

Back 65

one of several structures that lie on the ventral surface of the forebrain. It receives input from the hypothalamus and basal ganglia and sends axons that release acetylcholine to widespread areas in the cerebral cortex. The nucleus basalis is a key part of the brain's system for arousal, wakefulness, and attention.

Front 66

hippocampus

Back 66

from a latin word meaning seahorse. It is a large structure between the thalamus and the cerebral cortex, mostly toward the posterior of the forebrain. The hippocampus is critical for storing certain kinds of memories. People with hippocampal damage have trouble storing new memories, but they do not lose the memories they had before the damage occurred.

Front 67

central canal

Back 67

a fluid-filled channel in the center of the spinal cord

Front 68

ventricle

Back 68

four fluid-filled cavities within the brain. Each hemisphere contains one of the two large lateral ventricles. The third ventricle separates the left thalamus from the right thalamus. The third ventricle connects to the fourth ventricle in the center of the medulla.

Front 69

cerebrospinal fluid (CSF)

Back 69

a clear fluid similar to blood plasma

Front 70

meninges

Back 70

membranes that surround the brain and spinal cord. Fluid flows in the narrow space between the brain and the meninges. Although the brain has no pain receptors, the meninges do and inflammation of the meninges is very painful.

Front 71

hydrocephalus

Back 71

when the flow of CSF is obstructed it accumulates within the ventricles or in the subarachnoid space and increases pressure on the brain. When this occurs in infants, the skull bones may spread, causing an overgrown head.

Front 72

red nucleus

Back 72

Part of the midbrain. The red nucleus pertains to the shoulder and upper arm, in controlling movement. For instance, the red nucleus is what is active when we swing our arms when we walk or run. To remember the function of the red nucleus, use this mnemonic:

There is a person who likes to listen to her ipod while she jogs. She keeps her ipod strapped to her upper arm while she runs. Her ipod is red.



This mnemonic describes the function of the red nucleus. The circle on the ipod represents the nucleus shape, while the ipod being red, represents the colour of the red nucleus. This is how we remember the name. The function is remembered when we think about her ipod (the red nucleus) being strapped to her upper arm, which is what it controls. As most people swing their arms when they jog, this is a prime example of what the red nucleus does.

Front 73

anterior cingulate gyrus

Back 73

Location:

- looks like a collar enclosing the corpus-callosum



Functions:

- regulates blood pressure and heart rate

- rational cognitive functions such as reward anticipation, decision-making, empathy and emotion

- activation of ACG reduces capacity to learn how to use visual cues for anticipating rewards

- has been found to be active during reflective self-awareness



Mnemonics:

- Brain in a vat: if a brain in a vat is suddenly given a body, the ACG (along with another two areas) would be activated before many other parts of the brain because the being would be learning about itself while reflecting on its current state

Front 74

raphe system

Back 74

a subgroup of the reticular nuclei (reticular formation) of the brainstem, found in narrow longitudinal sheets along the raphae of the medulla oblongata, pons, and mesencephalon; they include many neurons that synthesize serotonin.