The NERVOUS System Functions of the Nervous System

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The NERVOUS System

The NERVOUS System

Functions of the Nervous System 1. Monitors stimuli (conditions that may require a response)

Functions of the Nervous System 1. Monitors stimuli (conditions that may require a response) both inside and outside the body. [sensory input] 2. Processes, makes decisions about how to respond to stimuli. 3. Causes a response by activating muscles, or glands [motor output]

Nervous – immediate Endocrine - delayed • Watch it respond

Nervous – immediate Endocrine - delayed • Watch it respond

Divisions of the Nervous System • Central Nervous System (CNS) -consists of the brain

Divisions of the Nervous System • Central Nervous System (CNS) -consists of the brain and spinal cord -interprets incoming sensory info and decides on response based on past experience, reflexes, and current conditions. • Peripheral Nervous System (PNS): -consists of the nerves extending from the CNS -these nerves link all of the parts of the nervous system

CNS

CNS

Divisions of the PNS • Somatic Nervous System -Offers voluntary control over skeletal muscles.

Divisions of the PNS • Somatic Nervous System -Offers voluntary control over skeletal muscles. • Autonomic Nervous System -regulates the activity of cardiac and smooth muscles. -regulates hormonal activity

Autonomic

Autonomic

Characteristics of Nerves • Nerves, also called Neurons, are the structural units of the

Characteristics of Nerves • Nerves, also called Neurons, are the structural units of the nervous system. -can live and function optimally forever (100+ years) -amitotic: they do not divide (cannot be replaced if destroyed) -high metabolic rate-require constant O 2 and glucose, die within a few minutes without O 2,

Neurons In the brain or spinal cord At a muscle or gland The CELL

Neurons In the brain or spinal cord At a muscle or gland The CELL BODY is housed in the brain or spinal cord, and the AXON extends to other organs (muscles or glands). The MYELIN SHEATH increases the speed of nerve impulses. Notice how the cell body and the axon terminal have branches. This is for communication purposes.

• Nodes of Raniver – where signals transmitted. • Multiple Sclerosis – Myelin

• Nodes of Raniver – where signals transmitted. • Multiple Sclerosis – Myelin Sheaths are gradually degraded. • ALS - lets read

How Neurons Act • Sodium and Potassium: Na+ and K+ are exchanged across the

How Neurons Act • Sodium and Potassium: Na+ and K+ are exchanged across the cell membrane to signal action. • Resting Potential: the inside of the cell membrane is more negatively charged than the outside. At rest, there is more Na+ outside than inside the cell. (More K+ is inside the cell)

Neurons communicate at synapses

Neurons communicate at synapses

Drugs can affect your nervous system. • Article

Drugs can affect your nervous system. • Article