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Nervous System
Jr / Sr. Vet Science
Mrs. Chotkowski
Nervous SystemFunctions:
• Detects and processes information
• Formulates responses
• Coordinates and controls all bodily activity
Nervous System• Sends and receives impulses
• Impulses are the electrical signals that travel through the nervous system and provide information to the brain.
Nervous System
Neurons:
• Most highly specialized cells in the body and have no powers of regeneration.
Nervous System
•Neurons Cont:•Have three parts:•1. Axons: efferent•2. Dendrites: afferent•3. Cyton or nerve cell
Nervous System
•Axon: Single
•Dendrite: Multiple(These refer to the processes of the cyton)
Nervous System
•Neurons cont:•Cyton:
The life center of the neuron
Nervous System
•Cyton Function:•Maintenance of its axons and dendrites. If cyton dies then the processes die and become non functional
Nervous System• Types of neurons:
• Sensory neurons: Carry impulses towards the brain and the spinal chord.
• Connecting neurons: Carry impulses from one neuron to another.
Nervous System
• Motor Neurons: Carry impulses away from the brain and spinal chord to the body.
Parts of a neuron:• Cell Body: Often called the soma.
Contains the cell nucleus.
• Dendrite: Branch-like, receives impulses
• Axon: Sends impulses away from the cells
Nervous System
•Synapse; Connections that
link the nervous system.
Nervous System
Space in between neurons: contains a chemical substance called a neurotransmitter. Helps impulses travel.
Nervous System
•Synapses Cont:In Parasympathetic ns and central ns, the conduction medium is:
Acetylcholine
Nervous System
•Sympathetic ns conductor is :
Noradrenaline
Nervous System
•Reflex Arc:Passage of a nerve impulse from:
Nervous System
•Receptor to sensory nerve to synapse to motor nerve to effector……..This is known as the reflex arc.
Nervous System
• Myelin (Sheath):
• Protective sheath around the neuron.
Nervous System•Central: CNS (Brain and Spinal Cord)
•Peripheral: PNS (Cranial and Spinal nerves)
•Autonomic: ANS……Cont.
Nervous System
•Autonomic NS cont:supplying smooth muscle cardiac and glands
Nervous System
I. Central Nervous System:
• Consists of the brain and spinal cord.
Nervous System• Brain: • Major Organ of the nervous
system.
• Meninges:
• Three-Layered protective covering of the brain.
Nervous System
• Cerebrum:• Largest part of the brain. It has
four lobes that receive and store information and are responsible for giving signals for voluntary movement.
Cerebellum:• Coordinates all muscle
activity and balance.
Nervous System
• Brainstem:
• Connects the brain to the spinal cord, and contains the medulla oblongata.
Nervous System
• Medulla Oblongata:
• Dictates all life functions including:
Nervous System
• Medulla Oblongata Cont:
• Heart rate, breathing, and reflex actions.
Nervous System
• Thalamus:
• Central relay system for all nerve impulses except smell.
Nervous System
• Thalamus Cont:
• The thalamus receives the impulses and then directs them to the proper part of the brain.
Nervous System
• Hypothalamus:
• Serves as a link between the nervous system and the endocrine system.
Nervous System
• Pituitary Gland:
• Secretes hormones important for reproduction and growth.
Nervous System
• Spinal Cord:
• Pathway for all impulses going to and from the brain. Connects to the medulla oblongata.
Nervous System
II. Peripheral Nervous System:
• Consists of nerves that relay information to and from the spinal cord.
Nervous System
• Sympathetic nervous system:
• Responsible for Emergency and stress responses:
• “fight or flight”
Nervous System
• Parasympathetic Nervous system:
• Seeks to maintain and restore normal body function, often called Homeostasis: a state of balance of the physiologic systems within the body.
