Interest Grabber Section 35 1 An Important Process
Interest Grabber Section 35 -1 An Important Process While walking along a dusty path, you begin to cough. As you continue your walk, a small insect comes flying toward you. You blink and then duck so that it misses you. These actions are just a few examples of homeostasis. Homeostasis is the process by which organisms keep internal conditions relatively constant despite changes in their external environments. 1. List three other examples of homeostasis that occur in organisms. 2. Why is homeostasis important to an organism?
Section Outline Section 35 -1 35– 1 Human Body Systems A. Organization of the Body 1. Levels of Organization 2. Types of Tissues B. Maintaining Homeostasis 1. A Nonliving Example 2. In the Body
Levels of Organization in a Multicellular Organism 1. Cells 2. Tissues – groups of similar cells that perform a single function 3. Organs – group of tissues that work together to perform a complex function 4. Organ Systems – group of organs that perform closely related functions 5. Organism
Humans contain 11 organ systems that work together to maintain a stable internal environment (Homeostasis).
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 Endocrine System Digestive System Excretory System Reproductive System Lymphatic System
Types of Tissues Muscle Tissue Epithelial Tissue Connective Tissue Nervous Tissue
1. Muscle Tissue Most abundant Controls the internal movement of materials Example: pushing food through the digestive system Controls the external movements of the entire body or parts of the body Example: typing on a keyboard
2. Epithelial Tissue Cover the surface of the body and line internal organs Consist of closely packed cells Example: lines chambers of the heart, makes up glands
3. Connective Tissue Holds organs in place and binds different parts of the body together Examples: tendons and ligaments Provides support for the body Pads and insulates the body
4. Nervous Tissue Receives messages from the body’s external and internal environments Analyzes the data and directs the response
Maintaining Homeostasis Feedback Inhibition – Process by which the product of a system shuts down the system or limits operation – Examples • Furnace in a house • Temperature regulation in the body • Human Menstrual Cycle
Examples of Feedback Inhibition Section 35 -1 Thermostat senses temperature change and switches off heating system Heating system turns on Room temperature decreases Thermostat senses temperature change and switches on heating system
Interest Grabber Section 35 -2 You’ve Got a Lot of Nerve! The nervous system controls and coordinates functions throughout the body. The nervous system is one of the body’s communication systems. Without communication, parts of the body could not work together smoothly.
Interest Grabber continued Section 35 -2 1. Think about tying the shoelace of a sneaker. Construct a flowchart that shows what happens between your eyes and your brain, and between your brain and your hands, when you tie a bow in the shoelace. 2. How would the communications be different if you tried to tie the shoelace with your eyes closed?
Section Outline Section 35 -2 35– 2 The Nervous System A. Neurons B. The Nerve Impulse 1. Resting Potential 2. The Moving Impulse 3. Threshold C. The Synapse
The Human Nervous System Function – controls and coordinates functions throughout the body and responds to internal and external stimuli
Neurons (Nerve Cells) Cells that transmit impulses (electrical signals) 3 types
Types of Neurons Sensory – carry impulses from the sense organs to the spinal cord and brain Motor – carry impulses from the brain and spinal cord to muscles and glands Interneurons (associative neurons) – connect sensory and motor neurons and carry impulses between them
Parts of Neurons Cell Body – Largest part of a typical neuron – Contains the nucleus and cytoplasm – Most metabolic activity of the cell takes place in the cell body Dendrites – Branched extensions – Carry impulses from the environment or from other neurons toward the cell body
Parts of Neurons (continued) Axon – Long fiber that carries impulses away from the cell body – Ends with axon terminals (small swellings) Myelin Sheath – Insulating membrane that surrounds some of the axons – Increases the speed at which the impulse can travel
A Neuron Section 35 -2 Nucleus Axon terminals Cell body Myelin sheath Nodes Axon Dendrites
Nerve Impulse Production depends on the movement of positively charged ions across a cell membrane
Resting Potential Difference in electrical charge across the cell membrane of a resting neuron Negative charge builds up on the inside of the membrane Positive charge builds up on the outside of the membrane
Figure 35 -6 Resting Potential Section 35 -2 Outside of cell Cell membrane Inside of cell
A nerve impulse begins when a neuron is stimulated by another neuron or by its environment.
Action Potential Reversal of charges Inside membrane gains a positive charge and the outside gains a negative charge
Figure 35 -7 An Impulse Section 35 -2 Action Potential At rest. 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. As the action potential passes, potassium gates open, allowing K+ ions to flow out. Action Potential 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. 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. As the action potential passes, potassium gates open, allowing K+ ions to flow out. Action Potential 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. 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. As the action potential passes, potassium gates open, allowing K+ ions to flow out. Action Potential 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. 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. As the action potential passes, potassium gates open, allowing K+ ions to flow out. Action Potential The action potential continues to move along the axon in the direction of the nerve impulse.
Threshold Minimum level of a stimulus that is required to activate a neuron Any stimulus that is stronger than the threshold will produce an impulse Any stimulus that is weaker than the threshold will produce no impulse
Synapse Location at which a neuron can transfer an impulse to another cell Gap (small cleft) which separates the axon terminal from the dendrites of the adjacent cell Terminals contain tiny sacs (vesicles) filled with neurotransmitters
Figure 35 -8 The Synapse Section 35 -2 Direction of Impulse Dendrite of adjacent neuron Axon Vesicle Receptor Axon terminal Synaptic cleft Neurotransmitter
Neurotransmitters Chemicals used by a neuron to transmit an impulse across a synapse to another cell Diffuse across the gap and attach themselves to receptors on the membrane of the neighboring cell Examples: Acetylcholine & Norepinephrine
Interest Grabber Section 35 -3 Brainiac Imagine that you are a computer systems engineer and your job is to design a computer that can perform all the functions of a human brain. 1. Which brainlike functions can already be performed by computers? 2. Which brainlike functions cannot be performed by computers? 3. How successful do you think you (or anyone) could be in designing a computer that can perform all the functions of the human brain? Explain your answer.
Section Outline Section 35 -3 35– 3 Divisions of the Nervous System A. The Central Nervous System B. The Brain 1. The Cerebrum 2. The Cerebellum 3. The Brain Stem 4. The Thalamus and Hypothalamus C. The Spinal Cord D. The Peripheral Nervous System 1. The Somatic Nervous System 2. The Autonomic Nervous System
Divisions of the Nervous System Central Nervous System Peripheral Nervous System
Central Nervous System Relays messages, processes information, and analyzes information Consists of the brain and the spinal cord Wrapped in connective tissue (meninges) Cerebrospinal fluid protects the brain and spinal cord and serves as a site for exchange
Brain Cerebrum – Site of intelligence, learning, and judgment Cerebellum – Coordinates and balances the actions of the muscles
Brain (continued) Thalamus – Receives messages from the sense organs and relays the information to the proper region of the cerebrum Brain Stem (pons and medulla oblongata) – “switchboard” regulating the flow of Hypothalamus information – Control center for between the recognition and brain and the analysis of hunger, rest of the body thirst, fatigue, anger, and body temperature
Spinal Cord Pathway that delivers messages to the brain or moves messages from the brain Responds to stimuli requiring reflex reaction Diagram of reflex arc
Reflex Arc Stimulus – Receptors (Sense Organs) Sensory Neurons Brain or Spinal Cord Response – Effectors (Muscles or Glands) Motor Neurons (Interneurons or Associative Neurons)
Peripheral Nervous System Receives information from the environment and relays commands from the central nervous system to organs and glands Consists of all of the nerves and associated cells that are not part of the brain and the spinal cord
Divisions of the Peripheral Nervous System Sensory Motor – Transmits impulses from sense organs the central to the central nervous system to the muscles or glands
Motor Division Somatic Nervous System – Regulates activities that are under conscious control – Examples: moving skeletal muscles Autonomic nervous System – Regulates activities that are automatic or involuntary – Examples: heartbeat, contraction of smooth muscles in the digestive system
Concept Map Section 35 -3 The Nervous System is divided into Central nervous system Peripheral nervous system Motor nerves which consists of that make up Somatic nervous system Autonomic nervous system which is divided into Sympathetic nervous system Parasympathetic nervous system Sensory nerves
Figure 35 -9 The Brain Section 35 -3 Cerebrum Thalamus Pineal gland Hypothalamus Cerebellum Pituitary gland Pons Medulla oblongata Spinal cord
Figure 35 -11 The Spinal Cord Section 35 -3 Gray matter Spinal nerve Central canal White matter Meninges
Interest Grabber Section 35 -4 Taking It All In Your senses—sight, hearing, smell, touch, taste—are constantly receiving information about your environment. Even if you are not thinking about it, your body is sensing and responding to conditions around you, such as the temperature of the room. 1. List ten things you observe about the room you are in. 2. Next to each observation, write the sense that you used to make that observation. 3. What sense did you use most?
Section Outline Section 35 -4 35– 4 The Senses A. Vision B. Hearing and Balance 1. Hearing 2. Balance C. Smell and Taste D. Touch and Related Senses
The Senses of Smell and Taste Section 35 -4 Olfactory (smell) bulb Taste sensory area Olfactory nerve Thalamus Cerebral cortex Smell receptor Nasal cavity Smell sensory area Taste bud Taste pore Taste receptor Sensory nerve fibers
Figure 35 -14 The Eye Section 35 -4 Vitreous humor Muscle Lens Fovea Aqueous humor Cornea Pupil Optic nerve Iris Blood vessels Ligaments Retina Choroid Sclera
Figure 35 -15 The Ear Section 35 -4 Hammer Anvil Stirrup Oval window Semicircular canals Cochlear nerve Cochlea Bone Auditory canal Tympanum Round window Eustachian tube
Interest Grabber Section 35 -5 Poster Designer Imagine that you are working with a local community group to help stop drug abuse among teenagers. Your first assignment is to design a drug abuse awareness poster. 1. Complete a brief sketch of your idea on a sheet of paper. What effects of drugs does your poster depict? 2. Why do you think teenagers will pay attention to your poster?
Section Outline Section 35 -5 35– 1 Drugs and the Nervous System A. Drugs That Affect the Synapse 1. Stimulants 2. Depressants 3. Cocaine 4. Opiates 5. Marijuana 6. Alcohol 7. Alcohol and Disease B. Drug Abuse
Commonly Abused Drugs Section 35 -5 Drug Type Medical Use Examples Effects on the body Stimulants Used to increase alertness, relieve fatigue Amphetamines Increase heart and respiratory rates; elevate blood pressure; dilate pupils; decrease appetite Depressants Used to relieve anxiety, irritability, tension Barbiturates Tranquilizers Slow down the actions of the central nervous system; small amounts cause calmness and relaxation; larger amounts cause slurred speech and impaired judgement Opiates Used to relieve pain Morphine Codeine Act as a depressant; cause drowsiness, restlessness, nausea
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