The Nervous System Flashcards
The nervous system is divided into The central or cerebrospinal nervous system
The peripheral nervous system
The autonomic nervous system
The central nervous system is composed of the brain, spinal cord, nerves/spinal cranial
The brain and spinal cord
Brain is referred to as what kind of center?
Command center
The average adult human brain weighs between 45-49 ounces (1.3-1.4kg)
Our brain uses 20% of the total oxygen we inhale
The skin holds 31 pairs of spinal nerves that branch out to muscles, and internal organs
A nerve appears as a whitish fiber or bundle of fibers, that transmits impulses and sensations to the brain or spinal cord and impulses from these to the muscles and organs
3 major areas of the brain are?
*Cerebrum
*Cerebellum
*Spinal Cord
The Cerebrum or forebrain, is the large, rounded structure of the brain that occupies the upper front part of the cranial cavity
Holds memories, allows you to plan, enables you to imagine and think. It allows you to recognize friends, read books and play games
The cerebellum appears as a wrinkled ball of tissue and regulates motor functions, muscle movement, balance, respiration and heart rate.
When you play the piano or hit a tennis ball you are activating the cerebellum
The spinal cord is composed of long nerve fibers, originates in the base of the brain and extends to the base of the spine.
Peripheral nervous system is any part of the nervous system that is not the brain or spinal cord.
Nerve cells:
Like other cells, the nerve cell or neuron has a nucleus, cytoplasm and a membrane
Nerve cells differ in appearance from other cells due to long (PNS) and short (central nervous system-CNS) threadlike fibers called axons and dendrites that extend from the cell. (peripheral nervous system-PNS)
Axons- (1) take information away from the cell body in the form of nerve impulses
Dendrites-(2) bring information to the cell body
The peripheral nervous system (PNS) serves as a relay between the spinal cord and the rest of the body. Nerves within the PNS perform two basic functions
Sensory or afferent nerves carry messages from tissues and organs to the brain and spinal cord. Sensory nerves send information from sensory receptors found in the skin, eyes, nose and tongue to the CNS. These nerves are located in the papillary area of the dermis.
Receptors (sensory nerve endings) send sensory messages like touch, temperature, sight, sound, taste, smell, pain and pressure to the brain for processing
Motor or efferent nerves carry 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 over from one side of the body to the other at the top of the spinal cord. This explains why a stroke on the left side of the brain affects the right side of the body.
-Signals from the right side of the brain go to the left side of the body and vice versa.
Autonomic Nervous System
The autonomic nervous system (ANS) is part of the central nervous system and is responsible for all involuntary body functions
The ANS governs all involuntary body functions such as breathing, blinking, sweating and digesting
The autonomic system consists of 3 subsystems
-Sympathetic-Accelerates the heart rate, constricts blood vessels and raises blood pressure
-Parasympathetic-Slows the heart rate, dilates blood vessels and lowers blood pressure
-Enteric-Governs the functions of the gastrointestinal tract
What is homeostasis?
Helps keep the body balanced
Study of the nerves
Nerves “carry” the messages from the central nervous system to the rest of the body and back to the central nervous system
There are 12 pairs of nerves that originate in the brain. They are called cranial nerves. They connect the brain directly with other parts of the body. Specifically the face, head and neck.
Since they are affected during facials and massages, an esthetician is primarily interested in the nerves of the face that include the
Fifth-Trifacial or Trigeminal
Seventh-Facial
Eleventh-Accessory
Cranial nerves
Fifth- Trifacial aka Trigeminal
Type-Sensory and Motor
Controls-Cheif sensory nerve of the face, sensations of the face, tongue, and teeth. Certain motor functions like biting or chewing
Has 3 major divisions
*Ophthalmic
*Maxillary
*Mandibular
Cranial nerves
Seventh-Facial
Type-Motor
Controls-Cheif motor nerve of the face, controls muscles of facial expression and sensation from skin and tongue (taste sensation)
Cranial nerves
Eleventh-Accessory
Type-Motor
Controls-Movement of the sternocleidomastoideus and trapezius to turn the head and shrug in the shoulders
Ophthalmic branch is the main nerve branch to the top third of the face, which further divides into
1.Supraorbital-Extends to the skin of the upper eyelid, eyebrow, forehead and scalp
2.Supratrochlear-Extends to the skin of the upper side of the nose and between the eyes
2a.Infratrochlear-Emerges on the skin of the upper eyelid and side of the nose
3.Nasal-Extends to the tip and lower side of the nose
Maxillary branch is the main nerve branch to the middle third of the face, which further divides into
4.Zygomatic-Extends to the side of the forehead, temple, and upper part of the cheek
5.Infraorbital-Extends to the lower eyelid, side of the nose, upper lip and mouth
Mandibular branch is the main nerve branch to the lower third of the face and further divides into
6.Auriculotemporal-Extends to the ear and to the area from the top of the head to the temple
7.Mental-Extends to the lower lip and chin
8.Posterior Auricular-Extends to the muscles behind and below the ear
9.Temporal-Extends to the muscles of the temple, the side of the forehead, the eyebrow, eyelid and upper cheek
10.Zygomatic (upper and lower)-Extends to the upper muscles of the cheek
11.Buccal-Extends to the muscles of the mouth
12.Marginal Mandibular- Extends to the muscles of the chin and lower lip
13.Cervical branch-Extends to the muscles on the side of the neck and platysma muscles
Cervical Nerves
14.Greater Occipital-Extends up the back of the scalp to the top of the head
15.Lesser Occipital-Extends into the muscles at the back of the skull
16.Greater Auricular-Extends into the side of the neck and external ear
17.Cervical Cutaneous-Extends into the side and front of the neck to the breastbone
The 11th cranial nerve is affected when using massage movements during a facial
- Accessory-Extends into the sternocleidomastoid and trapezius muscle
Arm and Hand nerves
1.Ulnar-Extends down the little finger side of the arm into the palm of the hand
2.Radial-Extends down the thumb side of the arm into the back of the hand
3.Median-Extends down the mid-forearm into the hand
4.Digital-Extends into the fingers of the hand
Leg and Foot Nerves
1.Sciatic-Begins in the lower back and runs through the buttock and down the lower limb
2.Tibial-Passes behind the knee and the common peroneal nerve
3.Common Peroneal-Runs alongside the sciatic nerve into the femur to the buttocks. Then ventures further down on its own along the knee and behind the fibula. The nerve then splits inside the neck of the fibula into the deep perineal and superficial peroneal
4.Deep Peroneal aka Anterior Tibial-A branch of the common peroneal
5.Superficial Peroneal-A branch of the common peroneal
6.Dorsal-The superficial nerve simply sits closer to the skin than the deep nerve and becomes the dorsal nerve
7.Saphenous-Begins in the thigh
8.Sural-Runs down the back of the leg to the outside of the foot and little toe
The digestive system is also known as the gastrointestinal system, breaks food down into chemical compounds that can be easily absorbed by cells or if not absorbed, eliminated from the body in waste products
The Digestive System
The digestive process begins as soon as food is ingested when enzymes secreted by the salivary glands (1) start breaking down the food
The Digestive System
Food travels down the pharynx (2) and through the esophagus (3) into the stomach (4) propelled by a twisting and turning motion of the esophagus called peristalsis. In the stomach, hydrochloric acid and several other enzymes further break down food
The Digestive System
One of these other enzymes, pepsin, is responsible for the breakdown of protein into polypeptide molecules and free amino acids, which are particularly important to the production of hair, skin, and nails
The Digestive System
As partially digested food passes from the stomach into the small intestines (5) the assimilation of nutrients begins.
-Water from food and fluids is absorbed in the small intestine
-Nutrients are absorbed by the vili which are fingerlike projections of the intestine walls, and transported through the circulatory system to the tissues and cells of the body
The Digestive System
Undigested food passes into the large intestine(6) also called the colon, which stores the waste for eventual elimination through the anal canal
-This process of digestion takes about nine hours to complete
-Excretion of undigested food and toxins regularly is important to the health of the intestines
The Excretory System
The excretory system works together with the lymphatic system
The excretory system eliminates waste/toxins from the body. Organs of the excretory system include
*The skin-Largest organ, releases water, carbon dioxide and other waste through the sweat glands
*The liver-Filters blood, metabolizing drugs and toxins
*The kidneys-Maintains fluid balance, regulate and filters minerals and toxins
*The large intestine-Part of the final stages of digestion
*The lungs-Removes carbon dioxide, at the base of the lungs, tiny air sacs called alveoli “take” the carbon dioxide off the red blood cells as the blood passes by and replace it with oxygen. Carbon dioxide is released into the environment when exhaled
The Endocrine System is composed of a group of specialized glands that regulate and control the growth and general health and reproduction of the body.
The Endocrine System
2 main types of glands are
-Duct glands also known as exocrine glands, manufacture substances such as sweat and oil that pass through small tube like ducts
Ductless glands also known as endocrine glands, release hormones into the bloodstream. Insulin, adrenaline and estrogen are examples of hormones secreted in the body
The Endocrine System directly affects hair growth, skin conditions and energy levels
The Reproductive system
Female reproductive system includes…
*Ovaries
*Fallopian tubes
*Uterus
*Vagina
Male reproduction system includes…
*Testes
*Prostate gland
*Penis
*Urethra
Endocrine overview
Glands
Pituitary-Produces critical hormones that controls various bodily functions. Often called the master gland.
Thyroid-Produces thyroid hormone which controls many activities in the body including how fast you burn calories and how fast your heart beats
Parathyroid-Produces parathyroid hormone through the use of four pea-sized glands that help keep your body in the right balance of calcium and phosphorus to protect bone, nerve and muscle health
Thymus-Produces T-cells which protect us from many viral threats and is considered a part of both the endocrine and lymphatic systems
Pancreas-Secretes enzymes that help break down carbohydrates, fats, proteins and acids, the main hormones secreted are insulin and glucagon, consists of the islets of langerhans which secrete amylin, insulin, glucagon, somatostatin and pancreatic polypeptide into the bloodstream
Adrenal-Produces a variety of hormones to help regulate metabolism, blood pressure, immune system and responses to stress including the “fight or flight” response.
Ovary and Testes-Determine female and male characteristics and are involved in sexual reproduction, secrete hormone steroids that help you grow and develop. Ovaries produce estrogen and progesterone. Male testes produce testosterone
Pineal-Produces the hormone melatonin, which plays a role in the sleep/wake cycle and the body response to sunlight
