Chapter 35-2 Nervous System

Figure 35-2 Human Organ Systems Part I Section 35-1 Nervous System Integumentary System Skeletal System Muscular System Circulatory System

Figure 35-2 Human Organ Systems Part I Section 35-1 Nervous System Integumentary System Skeletal System Muscular System Circulatory System

Figure 35-2 Human Organ Systems Part I Section 35-1 Nervous System Integumentary System Skeletal System Muscular System Circulatory System

Figure 35-2 Human Organ Systems Part I Section 35-1 Nervous System Integumentary System Skeletal System Muscular System Circulatory System

Figure 35-2 Human Organ Systems Part I Section 35-1 Nervous System Integumentary System Skeletal System Muscular System Circulatory System

Figure 35-2 Human Organ Systems Part 2 Section 35-1 Respiratory System Digestive System Excretory System Endocrine System Reproductive System Lymphatic/Immune Systems

35-2: The Nervous System ____________________ = (aka: communication system) consists of specialized cells that receive and relay information (by way of electrical signals) about activities within the body and monitors and responds to internal and external changes. The Nervous System The Neuron A. Neuron = Specialized cells, making up the nervous system, that carry impulses (messages)

The Neuron!! The _____________ part of the neuron is the ___________________. a) Most metabolic activity occurs here. __________: carry impulses ___________ the cell body. a) May be ________ dendrites attached to one cell body _________: The long fiber that carries impulses (messages) _________ from the cell body. a) Usually only ____ axon that is very__________. largest cell body Dendrites towards many Axon away 1 long

Anatomy of a neuron: Cell body: consists of nucleus and contents of the cytoplasm. Sites for ATP and Protein Production. Axon: Carries impulses away from cell body Axon Terminals: end at another neuron Dendrite: Receiver of impulses from the environment. Carries impulses toward cell body.

b) Some axons are covered by a _____________ sheath. 1. Some parts of the axons are left ____________ and are called __________. 2. A nerve impulse will _________ from node to node, making it _____________________.(Important for larger animals) 3. As you use a neural pathway ____________, myelin can develop, making it easier to ____________ information quicker. myelin exposed nodes jump travel faster repeatedly retrieve

Cross Section of the Axon

B. Impulses = C. 3 types of neurons (classified according to the direction of the impulse) 1. sensory neurons = carry impulses from ____________ to the 2. motor neurons = carry impulses from the _____________________ to _____________________. 3. interneurons = connect ___________ ______________ The electrical signals used for communication Sense organs brain and spinal cord brain and spinal cord muscles and glands sensory and motor neurons

Sensory-Interneuron-Motor Neurons

A General Overview of Neurons

not impulse difference active transport ATP II. The Nerve Impulse A. The Resting Neuron 1. Resting= ______ transmitting an _________. 2. Resting Potential: a) There are more ______ ions inside the nerve cell than outside the cell. b) There are more ____ ions outside the cell than inside the nerve cell. ** The ____________ in charge is maintained by _________________________ which uses _________. Nerve impulses rely on movement of (+) charged ions. not impulse K+ Na+ difference active transport ATP

c) A ______________________ uses _______ c) A ______________________ uses _______ __________ to pump Na+ ions ___ of the cell and K+ ions _____ the cell. d) Protein channels in the cell membrane allow ________ to leak out of the cell while keeping _________ from moving into the cell. e) The ________ that _________leave the cell also have a ____________ charge. f) Overall, the ________ of the cell is ________, and the outside of the cell is ____________. Na+/K+ pump active transport out into K+ ions Na+ ions proteins cannot negative inside negative positive

A Look at the Membrane Proteins

Neuron at resting potential ___________= Negative (compared to the outside) inside the cell and positive outside (polarized) Na + Na + Outside Na + Na + Na + Na + Na + Na + - - K + - K + - - - AXON - K + - K + - - K + Inside - Na + Na + Na + Na + Na + Outside Na + Na + Na + Na +

Figure 35-7 An Impulse Section 35-2

Figure 35-7 An Impulse Section 35-2

Figure 35-7 An Impulse Section 35-2

Figure 35-7 An Impulse Section 35-2

Reaching Resting Potential (show only first segment!)

B. The Moving Impulse 1. A neuron stays __________________ until it receives a ______________. a) An impulse begins when a neuron is stimulated by the __________________ or _______________________. b) The impulse allows ______ to move across the membrane. c) The impulse moves like a chain reaction down __________. at resting potential stimulus environment another neuron ions the axon

2. During an impulse, the membrane is ________________(+ inside, -outside) and ________________(-inside, +outside). a) The reversal of charges is known as an _______________ b) Action potentials move at 150 meters/second. depolarized repolarized action potential

C. The Action Potential (______________________) 1. Depolarization (+ inside, - outside) a) A stimulus causes a gate in the __________________ to open. b) Because the _________________ of Na+ is higher __________ the membrane, the sodium flows ________ the cell. (Now the inside becomes more + compared to the outside) 2. Repolarization (-inside, +outside) a) Depolarization causes the ___________ gate to immediately_________. b) ______ diffuses _______ of the neuron. reversal of charges Na+ channel concentration outside into K+ channel open K+ out

sodium gates will not open 3. Returning to Resting Potential a) The _____________ actively (ATP) pumps Na+ ___ of the neuron and K+ ______ the neuron. b) This ______________ the _________ ion distribution of the __________ neuron. D. Propagation of the Impulse 1. Nerve impulses are ____________________. They can occur at any point on the membrane and cause an impulse at the next point (like dominoes) 2. Unlike dominoes, impulses move in ______ __________ only because the membrane behind the impulse has a brief period where the __________________________. Na+/K+ pump out into reestablishes initial resting self-propagating one direction sodium gates will not open

E. Threshold 1. The strength of an ____________ is always the ___________. Threshold: The ________ level of stimulus that is required to _________ a neuron. 2. The ____________________ principle says that either a stimulus will be strong enough to produce an _________ or it will not. impulse same minimum activate all-or-none impulse

An Action Potential http://www.blackwellpublishing.com/matthews/channel.html Voltage gated channels & Proteins: http://highered.mcgraw-hill.com/sites/0072437316/student_view0/chapter45/animations.html#

III. The synapse (space between neurons) A. Axons end in B. Axon terminals contain C. Axon terminals make contact with D. Receptors = E. Effectors = small swellings called axon terminals vesicles filled with chemicals called neurotransmitters. receptors or effectors in an area called a synapse. Special sensory neurons in sense organs that receive stimuli from the external environment. Muscles or glands that bring about a coordinated response

Dendrite of adjacent neuron We know how impulses move down a neuron, but how does the signal travel from one neuron to another? Figure 35-8 The Synapse Section 35-2 Direction of Impulse Dendrite of adjacent neuron Axon Receptor Vesicle Axon terminal Synaptic cleft Neurotransmitter

vesicles fuse with the membrane When an impulse arrives at an axon terminal _______________________________ b. Through exocytosis, _______________________ __________________________________ The neurotransmitters attach to ___________ on the adjacent neuron _____________________________ _____________________. d. Na+ ions diffuse into the adjacent cell. If threshold is met, depolarization will occur and the impulse will continue. Once the neurotransmitter is released from the receptor sites, _____________________________________ _______________________________________ ________________________ vesicles fuse with the membrane are released into the synaptic gap/cleft neurotransmitters receptors changing the permeability of the membrane enzymes break the molecules down or they are reabsorbed by the axon terminals to be recycled.

Depolarized & Repolarized Membrane Activity Direction of Impulse

35-3 Divisions of the Nervous System Neurons working together forms a complicated communication system known as the Nervous System. Two major divisions of the Nervous System Central Nervous System (CNS) a. _________ messages b. Processes ____________. c. Analyzes ____________. d. Consists of : 1) _______________ Relays information information Brain

a) The brain: _____________ flow to the brain and is where many impulses ______________. b) Made up of over _________________ neurons. c) The human brain weighs _____ kilograms. Impulses originate 100 billion 1.4

2) The Spinal Cord a) Main Communication link between the __________ and the _______________ ___________. b) Carries _______________ of cells at once. c) _________ are processed ___________ in the spinal cord. rest of the brain body thousands Reflexes directly

2. Peripheral Nervous System (PNS) a. contains _______________________ ________________________________ b. Includes: _______________________ _______________________ c. Ganglia: ________________________ ___________ all the nerves that carry information to and from the CNS Cranial and spinal nerves and Ganglia collection of nerve cell bodies

The Divisions of the Nervous System Concept Map Section 35-3 The Nervous System is divided into Central nervous system Peripheral nervous system Sensory nerves Motor nerves which consists of that make up Autonomic nervous system Somatic nervous system which is divided into Sympathetic nervous system Parasympathetic nervous system

Peripheral Nervous System Divided into two divisions: Sensory Division: Motor Division: Sensory division and motor division Transmits impulses from sense organs (ie. Eyes, ears, taste buds) to central nervous system Basically: Sense organs  CNS Transmits impulses from central nervous system to muscles or glands (effectors) Basically: CNS  Effectors

Motor Division is divided into two systems _______________________ Regulates Somatic Nervous System conscious activities; such as the movement of skeletal muscles reflexes controlled by sensory neurons, motor neurons, and effectors producing a reflex arc

Reflex Arc 3 2 4 5 1 Example: You step on tack-Stimulus The tack stimulates sensory receptors on the skin The sensory receptors stimulate a sensory neuron The sensory neuron sends an impulse to an interneuron in the spinal cord A response signal is sent to a motor neuron The motor neuron stimulates an effector which makes you hand pull away 3 2 4 5 1

Autonomic Nervous System 2. __________________________ a. regulates b. The ANS is subdivided into 2 parts that have opposite effects on the organs they control. 1. Sympathetic Nervous System: Fight or Flight 2. Parasympathetic Nervous System: Rest and Digest Automatic or involuntary activities (ie. Heart, lungs, digestion,etc)

Sympathetic Nervous System Parasympathetic Nervous System Dilates pupil Constricts pupil Sympathetic Nervous System Parasympathetic Nervous System Stimulates saliva production Inhibits saliva production Constricts bronchi Dilates bronchi Slows down heart rate Speeds up heart rate Stimulates bile production Stimulates glucose production Stimulates peristalsis Inhibits peristalsis Inhibits urination Stimulates urination

Three General Function of the Nervous System

THE END !!!!

At rest. Figure 35-7 An Impulse Section 35-2 Action Potential As the action potential passes, potassium gates open, allowing K+ ions to flow out. Action Potential Action Potential At the leading edge of the impulse, the sodium gates open. The membrane becomes more permeable to Na+ ions and an action potential occurs. The action potential continues to move along the axon in the direction of the nerve impulse.

Figure 35-7 An Impulse Section 35-2 Action Potential At rest. As the action potential passes, potassium gates open, allowing K+ ions to flow out. Action Potential At the leading edge of the impulse, the sodium gates open. The membrane becomes more permeable to Na+ ions and an action potential occurs. The action potential continues to move along the axon in the direction of the nerve impulse.

Figure 35-7 An Impulse Section 35-2 Action Potential As the action potential passes, potassium gates open, allowing K+ ions to flow out. At rest. Action Potential The action potential continues to move along the axon in the direction of the nerve impulse. At the leading edge of the impulse, the sodium gates open. The membrane becomes more permeable to Na+ ions and an action potential occurs.

Figure 35-7 An Impulse Section 35-2 Action Potential As the action potential passes, potassium gates open, allowing K+ ions to flow out. At rest. Action Potential The action potential continues to move along the axon in the direction of the nerve impulse. At the leading edge of the impulse, the sodium gates open. The membrane becomes more permeable to Na+ ions and an action potential occurs.