THE NERVOUS SYSTEM Regents Biology.

Slides:



Advertisements
Similar presentations
The Human Nervous System
Advertisements

The Nervous System. To return to the chapter summary click escape or close this document. Human Nervous System.
2.2 THE NERVOUS SYSTEM.
The eleven organ systems of the human body work together to maintain homeostasis Homeostasis is the internal balance of the body Within the body are levels.
Regulation  control and coordination of life functions and activities  2 systems involved: 1. nervous- electrical system, brain,spine and nerves found.
The Nervous System 1.Control center for all body activities 2.Responds and adapts to changes that occur both inside and outside the body (Ex: pain, temperature,
The Nervous System.
Our electrochemical controls
Nervous System. Questions 1. What are the functions of the nervous system? 1. Receives information about what’s happening inside and outside the body.
Nervous System Maintaining homeostasis a billion messages at a time…
Chapter 8 Nervous System 5 Functions 1. Sensory function = receptors monitor external & internal body changes; providing input 5 Functions 1. Sensory function.
Lesson Overview Lesson Overview The Peripheral Nervous System SEC 33.4 The Peripheral Nervous System.
Regulation Nervous and Endocrine Systems. Parts of the nervous system… Brain Spinal Cord Nerves.
Nervous system. Neuron Briefly describe the following: Dendrites Axon Schwann cells Myelin sheath Nodes of Ranvier Neurilemma.
AGENDA MAY 25 Objective: Describe the structure and functions of human body systems. 1. EOC TEST 2. Human Body Systems – Nervous System Endocrine System.
TOPIC: The Nervous System AIM: How does the Nervous System help maintain Homeostasis? HW: TEXT BOOK READ PAGES Do Vocabulary Definitions for.
Anatomy and Physiology
The Nervous System - General Structure
The Nervous System.
9th Biology The Nervous System.
The Nervous System.
Nervous System Basics.
Anatomy and Physiology
The Nervous System.
The Nervous System Chapter 25.
THE NERVOUS SYSTEM.
Control of our body...
The Nervous System Chapter 5 Section 1.
Chapter 10 Nervous System Fundamentals.
Nervous system.
The Human Nervous System
NERVOUS SYSTEM REVIEW.
Nervous System.
ACOS 3 Relate major tissues and organs of the skeletal, circulatory, reproductive, muscular, respiratory, nervous, and digestive systems to their functions.
The Nervous System YuHui Lee Cindy Tsai.
The Nervous System.
The Nervous System
The Human Nervous System
TOPIC: Regulation AIM: How does the nervous system regulate the body
Chapter 7 The Nervous System.
The Nervous System Chapter 4 Section 1.
The Nervous system.
The Nervous System Objectives:
The Nervous System Chapter 35-2
19: The Nervous System Section Objectives:
Introduction to Anatomy & Physiology The Nervous System
Anatomy - Nervous System
The Nervous System.
The Nervous System Chapter 9  .
Chapter 19 Nervous System 19.1 Structure of the Nervous System Neurons Neurons are specialized nerve cells that help you gather information about your.
Nervous System.
Nervous System and Neurones
The Nervous System.
Autonomic Nervous System
Human Systems Nervous System Integumentary System Skeletal System
Nervous System.
The Nervous System 18.1.
The Nervous System  .
The Nervous System.
Peripheral Nervous System
The Nervous System -The nervous system controls and coordinates functions throughout the body. -The basic units of the nervous system are neurons.
Chapter 27 Lesson Overview
Nervous System.
Why are reflexes important?
Chapter 45 Nervous Regulation.
Anatomy-Nervous System
Digestive System Jeopardy
Presentation transcript:

THE NERVOUS SYSTEM Regents Biology

KEY WORDS axon cell body dendrite effector interneuron motor neuron OBJECTIVES Upon completion of this unit students will be able to: 1. Explain the functions of a nervous system and describe its basic types of structures. 2. Describe the neuron’s structure and the function of its parts. 3. Name different types of nerves and describe their functions. 4. List the changes that occur as an impulse travels along an axon. 5. Differentiate and give examples of effectors and receptors. 6. Compare and contrast the nervous responses/systems of different organisms. 7. Name the major parts of the brain. 8. Differentiate the CNS and the PNS. 9. Differentiate the autonomic nervous systems and the somatic nervous systems. 10. Describe a reflex arc and the all-or-none response. KEY WORDS axon cell body dendrite effector interneuron motor neuron receptor reflex arc sensory neuron stimulus

THE NERVOUS SYSTEM I. INTRODUCTION Why regulate? To deal with changes in the INTERNAL and EXTERNAL environment To maintain HOMEOSTASIS (stable internal environment) Responses to changes must be REGULATED (controlled and directed) and COORDINATED (occur in the right order or relationship) More complex organisms use the NERVOUS and ENDOCRINE systems for regulation and coordination

A. Protozoans Ameoba and paramecium do not have a nervous system but they do respond to stimuli from the environment. They move toward or away from stimuli. There are two types of taxis: CHEMOTAXIS AND PHOTOTAXIS B. Hydra This group does not have a central nervous system but does have a NERVE NET to receive stimuli from the environment.

C. Earthworm This group has a CENTRAL nervous system which consists of a brain (ganglia) and a VENTRAL nerve cord. Possessing a “CNS” allows directed responses to stimuli. The ventral nerve cord is a characteristic of INVERTEBRATES that have a nervous system.

D. Grasshopper Similar to that of the earthworm in that they also have a VENTRAL nerve cord and a BRAIN at one end of the body; the ANTERIOR end. In addition, more highly developed sensory abilities are illustrated by the development of the compound eyes and the ability to fly.

E. Human The nervous system consists of the Central and Peripheral Nervous Systems. The Central Nervous System (CNS) consists of the BRAIN and the SPINAL CORD The three major divisions of the brain and their functions are: DIVISION OF BRAIN FUNCTION CEREBRUM CONTROLS CONSCIOUS ACTS, PAIN AND OTHER SENSATIONS, THINKING, AND MEMORY CONTROL CEREBELLUM CONTROLS MUSCULAR COORDINATION AND BALANCE MEDULLA CONTROLS INVOLUNTARY ACTS LIKE BREATHING, HEARTBEAT, PERISTALSIS, AND BLOOD PRESSURE

Some other areas of the brain are the hypothalamus and the thalamus The SPINAL CORD lies within and is protected by the vertebrae of the spinal and has two functions: Connects the PNS to the brain Coordinates certain REFLEXES Impulses from sensory neurons travel up the spinal cord to the BRAIN and impulses from the brain are transmitted down through the spinal cord to MOTOR neurons. These impulses travel through peripheral nerves to the MUSCLES and GLANDS

THALAMUS CEREBRUM HYPOTHALAMUS PONS MEDULLA CEREBELLUM SPINAL CORD

2. The Peripheral Nervous System (PNS) includes the neurons which are outside the brain and spinal cord. The neurons connected to the brain are called CRANIAL nerves and the neurons which connect to the spinal cord are called SPINAL nerves. In terms of function, the PNS is divided into two systems, the SOMATIC and AUTONOMIC nervous systems. The SOMATIC Nervous System includes both sensory and motor neurons which connect the central nervous system to skeletal muscles. It is this system which controls VOLUNTARY movement. The AUTONOMIC Nervous System includes the Sympathetic and Parasympathetic systems. These motor neurons regulate many of the INVOLUNTARY activities in the body (heart rate, peristalsis, gland secretions, etc.). The SYMPATHETIC and PARASYMPATHETIC systems are opposite each other in function. If the sympathetic speeds up heart rate, the parasympathetic SLOWS it down to normal rate.

       a) The Sympathetic Nervous System does about the same as the hormone adrenaline. It gets the body ready for action (e.g., emergencies) by releasing the neurotransmitter NOREPINEPHRINE which speeds up heart rate, slows peristalsis, relaxes the bladder, dilates the bronchi and pupil, and constricts blood vessels b) The Parasympathetic Nervous System does the opposite. It brings the body back to normal by releasing the neurotransmitter ACETYLCHOLINE which slows down heart rate, speeds up peristalsis, constricts the bladder, constricts the bronchi and pupil, and dilates blood vessels.

A. Mechanisms of Nervous Regulation II. STRUCTURAL UNITS OF THE HUMAN NERVOUS SYSTEM A. Mechanisms of Nervous Regulation 1.  Receptors – SENSE ORGANS (SKIN, ETC.) RECEIVE THE STIMULUS THAT IS SENT THROUGH THE NEURON 2.  Nerve Cell (NEURON) 3.  Effector – WHERE IMPULSES END UP (TARGET) a.   Gland - INCREASE OR DECREASE SECRETION b.  Muscle – CONTRACT OR RELAX

Three types of neurons 1. SENSORY (a.k.a. afferent) neurons transmit impulses from sense organs (receptors, like the skin) to the CNS. 2. MOTOR (a.k.a. efferent) neurons transmit impulses away from the CNS to the effectors (muscles or glands) 3. INTERNEURON (a.k.a. associative or connector) neurons interpret and relay impulses between sensory and motor neurons. Impulses also originate here (in the brain or spinal cord).

Organization NERVE: bundles of neurons that usually transmit impulses very long distances 2. GANGLIA: enlarged structures which contain interneurons which serve to relay impulses.

D. Structure of an Individual Neuron (nerve cell) CELL BODY NUCLEUS DENDRITES TERMINAL BRANCHES AXON NODE OF RANVIER SCHWANN CELL NUCLEUS MYELIN SHEATH SCHWANN CELL SYNAPTIC KNOBS

E. Reflex Arc: The basic pathway of impulses from stimulus to response

All-or-none Response The all-or-none-response states that EITHER AN IMPULSE IS TRIGGERED OR NOT, DEPENDING ONLY ON WHETHER THE STIMULUS IS ABOVE OR BELOW THE THRESHOLD LEVEL (LIKE FIRING A GUN)