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.