Introduction: Structures of the nervous system 3.01 Remember the structures of the nervous system
Motor system Autonomic nervous system Sympathetic nervous system Parasympathetic nervous system Somatic nervous system 3.01 Remember the structures of the nervous system
Sympathetic nervous system Extends from the base of the brain, along both sides of the spinal column These nerves connect to all internal organs Parasympathetic nervous system The vagus nerve connects the medulla with organs of the upper body The pelvic nerve emerges from the spinal cord and connects with the organs of the lower body Autonomic nervous system
These nerves are located along the spinal cord. Connect skeleton, muscles and joints to the brain. Somatic nervous system 3.01 Remember the structures of the nervous system
What do we call a nerve cell? • A …neuron
NEURON • Nerve cell • Transmits a message from one cell to the next • Has a nucleus, cytoplasm, and cell membrane
The neuron has three parts • Dendrite • Axon • Myelin Sheath
DENDRITE DENDRITES • Nerve cell processes that carry the impulses to the cell body • May be one or many
AXON • Carries impulse away from cell body • Only one on a neuron AXON
Neurilemma AKA Myelin Sheath • Covering that speeds up the nerve impulse along the axon Myelin is a fatty substance that protects the axon
The BRAIN • Is a 3 pound mass of soft nerve tissue. • It contains over 100 billion neurons • Protected by the skull, the meninges and our spinal fluid.
Without an adequate supply of 02…our brain will start to die in 4-8 mins.!!!
Divided into 4 major parts • Cerebrum • Diencephalon • Cerebellum • Brain stem
CEREBRUM • The largest part of the brain.and is divided into 4 lobes. • Divided into left and right hemispheres by a deep grove called the “longitudinal fissure” • The elevated ridges are called “gyri”, they increase the surface area of the brain. • The fissures or grooves that separate the gyri are called “sulci”.
Where are the lobes? • Frontal- in front!! • Parietal- on top • Occipital- in back • Temporal- above the ears CEREBRAL FUNCTION= conscious thought, judgment, memory, reasoning and will power!!!
DIENCEPHALON • Located between the cerebrum and the midbrain. • Thalamus • Hypothalamus • Pineal body • Pituitary gland Function of hypothalamus= • autonomic nervous control • Temperature control • Appetite control • Emotions • Sleep control
CEREBELLUM • Located behing the pons and below the cerebrum. • Made up of two hemispheres. • Controls all skeletal muscle functions including: • Balance • Muscle tone • Coordination
BRAIN STEM • Made up of three parts. • It is the message pathway in and out of the brain. • Pons located in front of the cerebellum. It controls our respiration. • Midbrain controls vision and hearing. • Medulla Oblongata is responsible for heartrate and blood pressure.
Limbic System • Limbic system • Located in the center of the brain • Encircles the top of the brain stem.
12 cranial nerves 31 pairs of spinal nerves Peripheral nervous system 3.01 Remember the structures of the nervous system
SPINAL CORD • It begins at the foramen magnum and continues down to the 2nd lumbar vertebrae • It is soft and white in color • Surrounded by CSF • FUNCTIONS • Reflex center • Conduction pathway to and from the brain.
NERVES • They are a bundle of nerve fibers enclosed by connective tissue. • Sensory nerves carry impulses to the brain and spinal cord • Motor nerves carry impulses to muscles or glands • Mixed nerves contain both kinds of fibers.
Cranial Nerves • 12 pairs • Begin in the brain • Given a number and name. On Old Olympus Tiny Tops, AFinn, Very German Viewed All Hops.
HERE THEY ARE!! • I = Olfactory • II = Optic • III =Oculomotor • IV = Trochlear • V = Trigiminal • VI = Abducens • VII = Facial • VIII = Vestibulocochlear • IX = Glossopharyngeal • X = Vagus • XI =Accessory • XII = Hypoglossal
The brain covering is called… The MENINGES It is 3 layers thick; Dura mater Arachnoid Pia mater
DURA MATER • Outer covering of the brain. It lines the inside of the skull, it is tough and dense. It is fibrous connective tissue.
Arachnoid • The middle layer. • It resembles cobwebs.
PIA MATER • This layer covers the brain’s surface. It is comprised of blood vessels and is held together by connective tissue.
Subarachnoid space • It is between the arachnoid and pia mater. The space is filled with cerebrospinal fluid. The fluid acts like a “liquid shock absorber” for the brain.
VENTRICLES • The brain contains four cavities that are filled with spinal fluid. They are called cerebral ventricles. • Right and left- lateral • 3rd ventricle behind and below the laterals • 4th ventricle is below the 3rd, in front of the cerebellum.
CHOROID PLEXUS • A network of blood vessels lining the ventricles. • They help in the formation or production of spinal fluid.
Structures of the nervous system Remember this! 3.01 Remember the structures of the nervous system