Nervous System Flashcards
The nervous system does what
Coordinates and controls the operation of the human body
The central nervous system is responsible for
All voluntary body action, thoughts, reasoning, facial expression, and the functions of the 5 senses
The CNS is composed of
Brain and spinal cord
The brain description
Controls the nervous system
Referred to as the “command center”
Average weighs ~45-49 ounces
Brain uses 20% of the total oxygen we inhale
The 2 major areas of the brain
Cerebrum or forebrain
Cerebellum
Cerebrum def/description
Large, rounded structure of the brain that occupies the upper, front part of the cranial cavity
Center of higher mental functions (thought, emotion, and memory)
Holds memories, allows planning, enables imagination, and thinking
Allows recognition of friends, reading books, and playing games
Cerebellum def and description and example
Appears as a wrinkled ball of tissue and regulates motor function, muscle movement, balance, respiration, and heart rate
Ex of use - playing piano or hitting a tennis ball
Spinal cord def/description
Composed of long nerve fibers
Originates in the base of the brain and extends to the base of the spine
Holds 31 pairs of spinal nerves that branch out to muscles, internal organs, and skin
Peripheral nervous system def and description
Any part of the nervous system that isn’t the brain or spinal cord
Network of nerve cells that carries messages to and from the central nervous system
The PNS is made up of the
Sensory (afferent) and motor (efferent) systems
Nerve cells description
Has a nucleus, cytoplasm, and membrane
Differ in appearance from other cells due to long PNS and short CNS threadlike fibers that extend from the cell that are called axons and dendrites
Axons def
Take information away from the cell body in the form of nerve impulses
Dendrites def
Bring information to the cell body
3 types of nerves
Sensory
Motor
Mixed
Sensory nerves function and location
Carry messages from tissues and organs to the brain and spinal cord
Located in the papillary area of the dermis
Receptors (sensory nerve endings) function
Send sensory messages (touch, temperature, sight, sound, taste, smell, pain, and pressure) to the brain
Motor nerves function
Carries messages from the brain to the muscles or glands
When the brain sends a message, motor nerves receive the message and cause a muscle to contract or expand
Motor nerves cross from one side of the body to the other at the top of the spinal cord
Mixed nerves description/function
Sensory-motor nerves
Transmit messages in both directions at once
Reflex action def
Interaction of sensory and motor nerves
Autonomic nervous system def
Is part of the central nervous system and is responsible for all involuntary body functions (blinking, breathing, sweating)
Closely associated with the digestive, excretory, respiratory, circulatory, endocrine, reproductive, and integumentary systems
The three subsystems of the ANS
Sympathetic
Parasympathetic
Enteric
Sympathetic system function
Accelerates heart rate, constricts blood vessels, and raises blood pressure
Parasympathetic function
Slows the heart rate, dilates blood vessels, and lowers blood pressure
Enteric function
Governs the functions of the gastrointestinal track
Nerves function
“Carry” the messages form the CNS to the rest of the body and back to the CNS
How many cranial nerves are there
12
Cranial nerves def
Connect the brain directly with other parts of the body (specifically face, head, and neck)
Which cranial nerves are we most interested in
Fifth = trigerminal or trifacial
Seventh = facial
Eleventh = accessory
The 12 cranial nerves and their controls
- Olfactory = sense of smell (sensory)
- Optic = sense of sight (sensory)
- Oculomotor = moves eye and constricts the pupil (motor)
- Trochlear = moves eye (motor)
- Trifacial = chief sensory nerve of the face (motor and sensory)
- Abducent = moves eye laterally toward the ear (motor)
- Facial = chief more nerve of the face (motor)
- Acoustic or auditory = sense of hearing and balance (sensory)
- Glossopharyngeal = sense of taste (sensory and motor)
- Vagus = motion and sensation of the ear, pharynx, and pneumogastric (sensory and motor)
- Accessory = movement of the Sternocleidomastoid and trapezius to turn the head and shrug the shoulders (motor)
- Hypoglossal = motion of the tongue (motor)
The 3 divisions of the 5th cranial (trifacial) nerve
Ophthalmic
Maxillary
Mandibular
Methods to stimulate muscular tissue and nerves
Massage
Electric current
Temperature
Facial nerve (7th cranial) description
Emerges from the brain at the lower part of the ear; primary motor nerve of the face
Controls muscles of facial expression and sensation from the skin and tongue
Digestive system def/description
Also known as the gastrointestinal system; breaks down food into chemical compounds that can be easily absorbed by cells or if not absorbed, eliminated from the body in waste
The digestive system process (5)
Food is ingested
Enzymes secreted by salivary glands start breaking down the food
Food travels down the pharynx and through esophagus into the stomach - propelled by a twisting and turning motion of the esophagus = peristalsis
Partially digested food passes from stomach into the small intestine where assimilation of nutrients begins
Undigested food passes into the large intestine or colon which stores waste for eventual elimination
Excretory system def/description
Works together with the lymphatic system; eliminates waste/toxins from the body in
Organs in the excretory system
Skin
Liver
Kidneys
Large intestine
Lungs
The skin description
Covers the body’s surface of nearly 20 sq ft
Body’s largest organ
Releases water, carbon dioxide, and other waste through sweat glands
Liver description
Filters blood, metabolizing drugs and toxins
Regulates most chemical levels in the blood
Excretes bile, which helps break down fats, preparing them for further digestion and absorption — the liver converts and neutralizes ammonia from circularity system to urea, which is then carried, through the bloodstream, to the kidneys for excretion
Kidneys description
Maintain fluid balance
Regulate and filter minerals and toxins
Regulate blood pressure
Receive urea from the liver and pass the urea through small tube-like structures called nephrons — these structures filter waste products and water, allowing usable nutrients to be reabsorbed into the blood
Lungs description
Removes carbon dioxide
At the base of the lungs, tiny air sacs (alveoli) “take” the carbon dioxide off the red blood cells as the blood passersby and replace it with oxygen
The respiratory system is made up of
Organs and tissues that help you breathe
