Term
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Definition
The body's control center and communication network.
It shares in the maintenance of homeostasis with the endocrine system. |
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Term
Central Nervous System (CNS) |
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Definition
| Consists of the brain and spinal cord. |
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Term
The Peripheral System (PNS) |
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Definition
| Consists of the afferent peripheral system (sensory neurons) and the efferent peripheral system (motor neurons). |
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Term
The Efferent Peripheral System
(motor neurons) |
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Definition
| Can be subdivided into the somatic nervous system, which sends signals to skeletal muscles, and the autonomic nervous system (ANS), which sends signals to cardiac and smooth muscles and glands. |
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Term
The Autonomic Nervous System (ANS)
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Definition
| Has two divisions: The sympathetic division, which stimulates and speeds up activity, and the parasympathetic division, which restores or slows down certain activities but stimulates the body's vegetative activities. |
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Term
Classification of Nerve Cells
Neurons |
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Definition
| Nerve cells that transmit nerve impulses in the form of electrochemical changes. |
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Term
Classification of Nerve Cells
Nerve |
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Definition
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Term
Classification of Nerve Cells
Neuroglia Cells |
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Definition
Cells that support and protect the neurons.
There are different types of neuroglia cells, and, unlike neurons, they do not conduct impulses.
Neuroglia means nerve glue.
Over 60% of all brain cells are neuroglia cells. |
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Term
Functional Classification of Neurons
Receptors |
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Definition
| Detect stimuli in our environment. |
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Term
Functional Classification of Neurons
Sensory or Afferent Neurons |
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Definition
| Receive the impulse directly from the receptor site. They are unipolar neurons. |
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Term
Functional Classification of Neurons
Internuncial or Association Neurons |
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Definition
| Found in the brain and spinal cord. They transmit the impulse for interpretation and processing. They are multipolar neurons. |
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Term
Functional Classification of Neurons
Motor or Efferent Neurons |
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Definition
| Bring about the reaction to the stimulus. They are multipolar neurons. |
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Term
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Definition
| States that if a nerve fiber carries any impulse, it will carry a full strength impulse. |
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Term
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Definition
| An involuntary reaction to an external stimulus. |
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Term
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Definition
The pathway that causes a reflex.
Has five components:
1. A sensory receptor in the skin
2. A sensory or afferent neuron
3. Association or internuncial neurons in the spinal cord
4. A motor or efferent neuron
5. An effector organ |
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Term
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Definition
A continuation of the medulla oblongata.
Is made of 31 segments, each giving rise to a pair of spinal nerves.
Is protected by spinal meninges
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Term
The Spinal Cord
Layers of the Spinal Meninx
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Definition
The outermost spinal meninx is the dura mater or tough mother.
The middle spinal meninx is the arachnoid mater or spider layer.
The innermost spinal meninx is the pia mater or delicate mother.
Between the dura mater and the arachnoid is a space called the subdural space, which contains serous fluid.
Between the arachnoid and the pia mater is the subarachnoid space in which the cerebrospinal fluid circulates. |
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Term
Functions of the Spinal Cord |
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Definition
Conveys sensory impulses from the periphery to the brain (ascending tracts) and conducts motor impulses from the brain to the periphery (descending tracts).
Integrates reflexes.
Each pair of spinal nerves connects to a segment of the spinal cord by two points of attachment called the roots. |
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Term
Functions of the Spinal Cord
Spinal Cord Roots |
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Definition
The posterior or dorsal root is sensory and connects with the posterior or dorsal gray horn of the spinal cord.
The anterior or ventral root is motor and connects with the anterior or ventral gray horn of the spinal cord. |
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Term
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Definition
- There are eight pairs of cervical nerves.
- There are 12 pairs of thoracic nerves.
- There are five pairs of lumbar nerves.
- There are five pairs of sacral nerves.
- There is one pair of coccygeal nerves.
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Term
The 12 Cranial Nerves and their Functions
Olfactory Nerve |
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Definition
Sensory
Conveys impulses related to smell. |
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Term
The 12 Cranial Nerves and their Functions
Optic Nerve |
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Definition
Sensory
Conveys impulses related to sight. |
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Term
The 12 Cranial Nerves and their Functions
Oculomotor Nerve |
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Definition
Both Sensory and Motor:
Controls movements of the eyeballs and upper eyelid. It's parasympathetic function controls constriction of the pupil. |
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Term
The 12 Cranial Nerves and their Functions
Trochlear Nerve |
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Definition
Both Sensory and Motor
Controls movement of the eyeball.
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Term
The 12 Cranial Nerves and their Functions
Trigeminal Nerve |
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Definition
Both Sensory and Motor
Note: divided into three branches: the opthalmic branch, the maxillary branch, and the mandibular branch.
Controls chewing movements and senses touch, temperature, and pain in the teeth and facial area. |
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Term
The 12 Cranial Nerves and their Functions
Abducens Nerve |
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Definition
Both Sensory and Motor
Controls movement of the eyeball. |
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Term
The 12 Cranial Nerves and their Functions
Facial Nerve |
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Definition
Both Motor and Sensory:
Controls the muscles of facial expression. It also senses taste. Its parasympathetic function controls the tear and salvari glands. |
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Term
The 12 Cranial Nerves and their Functions
Vestibulocochlear Nerve |
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Definition
Sensory:
Note: divided into two branches: the vestibular branch responsible for balance and the cochlear branch responsible for hearing.
Transmits impulses related to equilibrium and hearing. |
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Term
The 12 Cranial Nerves and their Functions
Glossopharyngeal Nerve |
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Definition
Both Motor and Sensory
Controls swallowing and senses taste. Its parasympathetic function controls salivary glands. |
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Term
The 12 Cranial Nerves and their Functions
Vagus Nerve |
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Definition
Both Motor and Sensory:
Note: supplies the head, pharynxm bronchus, esophagus, liver, and stomach
Controls skeletal muscle movements in the pharynx, larynx, viscera, and ear. Its parasympathetic functions control viscera in the thorax and abdomen. |
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Term
The 12 Cranial Nerves and their Functions
Accessory Nerve |
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Definition
Both Motor and Sensory
Helps control swallowing and movement of the head.
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Term
The 12 Cranial Nerves and their Functions
Hypoglossal Nerve |
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Definition
It is both Motor and Sensory
Controls muscles involved in swallowing and speech. |
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Term
Principal Parts of the Brain |
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Definition
Divided into four main parts:
1. The brainstem consisting of the medulla oblongata, the pons varolii, and the
midbrain.
2. The diencephalon consisting of the thalamus and the hypothalamus.
3. The cerebrum consisting of two hemispheres
4. The cerebellum.
*It is protected by the cranial bones, the cranial meninges, and the cerebrospinal fluid. |
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Term
Principal Parts of the Brain
Cerebrospinal Fluid |
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Definition
| Acts as a shock absorber for the central nervous system and circulates nutrients. In the brain, it circulates in the subarachnoid space and the four ventricles. |
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Term
The Anatomy and Functions of the Brainstem
Medulla Oblongata |
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Definition
| Contains all the ascending and descending tracts that connect the spinal cord with the brain. Some of these tracts cross in the medulla, known as decussation of pyramids. This explains why motor functions on one side of the cerebrum control muscular movements on the opposite side of the body. |
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Term
The Anatomy and Functions of the Brainstem
The Reticular Formation of the medulla |
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Definition
| Controls consciousness and arousal. The three vital reflux centers control the diameter of blood vessels, heartbeat, and breathing rates. |
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Term
The Anatomy and Functions of the Brainstem
The Pons Varolii |
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Definition
| A bridge that connects the spinal cord with the brain and parts of the brain with each other. It also helps control breathing. |
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Term
The Anatomy and Functions of the Brainstem
The Midbrain or Mesencephalon |
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Definition
| Contains the dorsal tectum, a reflex center, that controls movement of the head and eyeballs in response to visual stimulation and movement of the head and trunk in response to auditory stimuli. |
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Term
The Anatomy and Functions of the Diencephalon
Thalamus |
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Definition
| A relay station for sensory impulses and an interpretation center for recognition of pain, temperature, and crude touch. |
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Term
The Anatomy and Functions of the Diencephalon
Hypothalamus |
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Definition
| Controls functions related to homeostasis: it controls the autonomic nervous system; iit receives sensory impulses from the viscera; it controls the pituitary gland; it is the center for mind-over-body phenomena; it controls our thirst center; and maintains our waking and sleep patterns. |
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Term
The Cerebrum: Structure and Function
Cerebrum
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Definition
The surface is composed of gray matter and is called the cerebral cortex. Below the cortex is the white matter.
The surface of the cortex has motor areas to control muscular movements, sensory areas for interpreting sensory impulses, and association areas concerned with emotional and intellectual processes.
A longitudinal fissure seperates the cerebrum into two hemispheres. Folds in the surface of the hemispheres are called gyri with intervening grooves called sulci.
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Term
The Cerebrum: Structure and Function
Cerebrum Hemispheres
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Definition
| Each hemisphere is divided into four main lobes: Frontal lobe, parietal lobe, temporal lobe, and the occipital lobe. |
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Term
The Cerebrum: Structure and Function
Frontal Lobe |
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Definition
| Controls voluntary muscular movements, moods, aggression, smell reception, and motivation. |
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Term
The Cerebrum: Structure and Function
Parietal Lobe |
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Definition
| Evaluates sensory information concerning touch, pain, balance, taste, and temperature. |
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Term
The Cerebrum: Structure and Function
Temporal Lobe |
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Definition
| Evaluates hearing, smell, and memory. It is a center for abstract thought and judgement decisions. |
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Term
The Cerebrum: Structure and Function
Occipital Lobe |
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Definition
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Term
The Cerebrum: Structure and Function
Corpus Callosum |
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Definition
| A bridge of nerve fibers that connects the two hemispheres of the cerebrum. |
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Term
The Cerebellum: Structure and Function
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Definition
Consists of two primarily seperated hemispheres connected by a structure called the vermis. The cerebellum is shaped like a butterfly.
It funtions as a center for coordinating complex muscular movements, maintaining body posture, and balance. |
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Term
Autonomic Nervous System (ANS) |
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Definition
A subdivision of the efferent peripheral nervous system.
It regulates internal organs by controlling glands, smooth muscle, and cardiac muscle. It maintains homeostasis by regulating heartbeat, blood pressure, breathing, and body temperature.
It helps us control emergency situations, emotions, and various physical activities.
It consists of two subdivisions: the sympathetic division, and the parasympathetic division. |
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Term
Autonomic Nervous System (ANS)
Sympathetic Division |
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Definition
Deals with energy expenditure and stressful situations by increasing heartbeat rates and breathing. Its fibers arise from the thoracic and lumbar regions of the spinal cord. It uses acetylcholine as a neurotransmiter in the preganglionic synapses and norepinephrine or noradrenaline at postganglionic synapses.
Prepares us for physical activity: it increases blood pressure, heart rate, breathing, and sweating; it releases glucose from the liver for quick energy. It is also known as the fight-or-flight system.
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Term
Autonomic Nervous System (ANS)
Parasympathetic Division |
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Definition
Functions in restoring the body to a nonstressful state. Its fibers arise from the brainstem and the sacral region of the spinal cord. It uses acetylcholine at both the preganglionic and and postganglionic synapses as a neurotransmitter.
Counteracts the effects of the sympathetic division: it slows down heart rate, lowers blood pressure, and slows breathing. It also controls digestion, urinaion, defecation, and constriction of the pupil. It is known as the rest and repose system. |
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Term
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Definition
The senses of smell and taste are initiated by the interactions of chemicals with sensory receptors on the tounge and in the nose.
The sense of vision occurs due to the interactions of light with sensory receptors in the eye.
The senses of hearing and balance occur due to the interaction of sound waves for hearing and motion for balance with sensory receptors in the ear. |
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Term
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Definition
The sense of smell or olefactory sense, occurs because molecules in the air become dissolved in the mucous epithelial lining of the superior nasal conchae of the nose.
Bipolar sensory enurons transfer these chemical impulses to the olefactory bulbs that connect with association neurons of the olefactory cortex in the temporal and frontal lobes of the cerebrum.
A small number of receptors in the nose detect a great variety of odors via brain interpretation of receptor combinations. |
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Term
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Definition
Taste buds are found on certain papilae of the tounge on the palate of the roof of the mouth, and part of the pharynx.
Taste buds consist of two types of cells: epithelial cells that form the exterior capsule and taste cells that form the interior of the taste bud.
The taste chemical is first dissolved in the fluid of saliva. These sensory impulses are conducted by the facial, glossopharyngeal, and vagus nerves to the taste cortex of the parietal lobe of the cerebrum for interpretation. |
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Term
The Sense of Taste (continued) |
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Definition
There are four major types of taste sensations: bitter, strongly detected at the back of the tongue; sweet and salty, detected at the tip of the tongue; and sour, detected more strongly by the taste buds on the sides of the tongue.
Taste sensations are also influenced by olefactory sensations. |
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Term
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Definition
The eyes are organs of sight. Eyelids and eyelashes protect the eyes from foreign objects. Tears, produced by the lacrimal glands, lubricate the eyes.
Tears contain the bacteriolytic enzyme lysozome. |
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Term
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Definition
The wall of the eye is composed of three layers: the sclera, the choroid, and the retina.
The interior of the eye is divided into two fluid filled compartments. The anterior compartment is filled with aqueous humor; and the posterior compartment is filled with vitreous humor. These fluids help maintain ocular pressure, bend light, and hold the retina and lens in place. |
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Term
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Definition
| The outermost, white, hard layer composed of tough collagenous connective tissue. |
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Term
Anatomy of the Eye
Cornea |
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Definition
| The transparent part of the sclera that allows light to enter the eye. |
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Term
Anatomy of the Eye
Choroid |
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Definition
| The second layer and contains blood vessels and pigment cells. It is black in color and absorbs light to prevent reflection that could impair vision. |
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Term
Anatomy of the Eye
Retina |
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Definition
The innermost layer of the eye. It contains light sensitive cells called rods and cones.
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Term
Anatomy of the Eye
Rods and Cones |
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Definition
There are more rods and cones in the retina. These light sensitive cells have two functions. Rods are very sensitive to light and function in dim light; cones produce color sensations and require alot of light.
The rods and cones synapse with the bipolar sensory cells of the retina. These cells synapse with the optic nerve, which reaches the thalamus of the brain to synapse with the visual cortex of the occipital lobe of the cerebrum for interpretation. |
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Term
Anatomy of the Eye
Ciliary Body |
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Definition
| Holds the hard, biconvex, transparent lens in place. |
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Term
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Definition
| The colored part of the eye surrounding the pupil. It regulates the amount of light that can enter the pupil. |
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Term
The Sense of Hearing and Equilibrium |
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Definition
The external, middle, and inner ear contain the organs of balance or equilibrium, and hearing.
The visible, flexible, external ear is called the auricle. It directs sound waves to the ear canal called the external auditory meatus.
The ear canal is lined with hairs and ceruminous glands that produce earwax to protect the delicate eardrum, or tympanic membrane, from foreign objects.
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Term
The Sense of Hearing and Equilibrium
The Middle Ear |
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Definition
The middle ear contains the auditory ossicles: the malleus or hammer, the incus or anvil, and the stapes or stirrup. These bones transmit sound vibrations from the tympanic membrane, which vibrates due to sound waves, to the oval window.
There are two openings on the medial side of the inner ear: the oval window and the round window, which connect the middle ear to the inner ear.
The middle ear also contains the auditory or eustachian tube, which connects to the pharynx and allows for equalized air pressure between the outside world and the middle ear, thus not impairing hearing. |
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Term
The Sense of Hearing and Equilibrium
The Inner Ear |
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Definition
| The inner ear consists of fluid-filled interconnecting chambers and tunnels in the temporal bone. It contains the cochlea involved in hearing and the semicircular canals and vestibule involved in balance. |
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