The body ’ s communication systems help maintain homeostasis. A stimulus is anything that causes a response. –Responses can be chemical, cellular, or behavioral. 1.Chemical: insulin, growth hormone, adrenaline 2.Cellular: White Blood cells 3.Behavioral: Body temperature, walking into sunlight –The nervous and endocrine systems respond to stimuli.

The nervous system controls thoughts, movement, and emotion. The endocrine system controls growth, development, and digestion.

The nervous and endocrine systems have different methods and rates of communication. The nervous system works quickly, using chemical and electrical signals. –divided into central nervous system (CNS) and peripheral nervous system (PNS) –Central: brain & spinal cord –Peripheral: all other nerves spinal chord nerves

The endocrine system works more slowly. –only chemical signals –signals move through bloodstream –physically unconnected organs receptor target cell not a target cell bloodstream hormone

Endocrine or Nervous? Rate at which your fingernails grow? Blinking? Heart Rate? Hair growth? Knee jerk reflex? Amount of Insulin Released? Endocrine Nervous Endocrine Nervous Endocrine

Neurons are highly specialized cells. A neuron has three parts. –cell body has nucleus and organelles 1 Cell body

–dendrites receive impulses Neurons are highly specialized cells. A neuron has three parts. –cell body has nucleus and organelles 2 dendrites

–axon carries impulses 3 axon –dendrites receive impulses Neurons are highly specialized cells. A neuron has three parts. –cell body has nucleus and organelles

Neurons have other structures to transmit signals. –Schwann cell (affected by MS)

–synapse synapse Neurons have other structures to transmit signals. –Schwann cell

–terminal –synapse Neurons have other structures to transmit signals. –Schwann cell axon termin al

Neurons receive and transmit signals. Resting potential means no signal is being transmitted. –more Na + outside of cell –more K + inside of cell Inside of cell – Outside +

An action potential is a moving electrical impulse. –It is generated by a stimulus. –Na + enters, and cell becomes positively charged. –K + leaves, and area of positive charge moves.

A chemical signal passes between neurons. –Impulse reaches terminal. impu lse

A chemical signal passes between neurons. –Impulse reaches terminal. impu lse

A chemical signal passes between neurons. –Impulse reaches terminal. impu lse –Neurotransmitters released into synapse.

A chemical signal passes between neurons. –Impulse reaches terminal. –Neurotransmitters released into synapse. impu lse synapse recep tor vesicl es neurotrans mitter –Neurotransmitters stimulate next cell.

Neuron Visual Questions (pg. 878) 1. When a neuron is at rest, what is the charge of its inner membrane? 2. What causes an area of the inner membrane to become positively charged? 3. How does an area of positive charge, or impulse, move down the axon of a neuron? 4. How is the negative charge of the axon’s inner membrane restored? 5. What happens when the impulse reaches the axon terminal? 6. How do neurotransmitters generate an impulse in an adjacent neuron?

The CNS and PNS pass signals between one another. 1.Sensory receptor generates impulse. 2.Impulse travels on sensory neurons 3.PNS passes impulse to CNS. 4.CNS interprets impulse. 5.CNS passes impulse to PNS. 6.PNS motor neurons stimulate a response.

The CNS processes information. The brain has three parts. –cerebrum controls thought, movement, emotion –cerebellum allows for balance –brain stem controls basic life functions midbrain pons medulla oblongata Brain stem

Lobes of the Brain Frontal: responsible for personality, reasoning, judgment, coordinates speech & voluntary movement Temporal: speech interpretation & hearing Occipital: Vision Parietal: Interprets information from sense of touch

The brain stem has three parts. –midbrain controls some reflexes –pons regulates breathing –medulla oblongata controls heart function, swallowing, coughing midbrain medulla oblongata pons

The spinal cord controls reflexes. –sensory neuron sends impulse to spinal cord –spinal cord directs impulse to motor neuron –does not involve the brain interneuron motor neurons sensory neuron

The PNS links the CNS to muscles and other organs.

3 Common Technologies to study the brain –CT uses x-rays to view structure. –PET detects activity, where glucose is used, in the brain. –MRI uses magnetic fields and radio waves to view structure.

Different neurotransmitters relate to different functions. –some stimulate impulses –some prevent impulses synapse Normal neurotransmitter receptor

Addiction is the physiological need for a substance. Tolerance occurs when more drug is needed to produce an effect. Drugs might cause desensitization or sensitization. –desensitization: more neurotransmitter leads to fewer receptors –sensitization: less neurotransmitter leads to more receptors. When the amount of neurotransmitter becomes abnormal, the adjacent neuron adapts.

Stimulants cause more action potentials –may increase neurotransmitter in synapse –may decrease removal of neurotransmitter in synapse cocaine neurotransmitter synapse

Depressants cause fewer action potentials. –may produce neurotransmitter that prevent impulses –may slow release of neurotransmitter that generates impulses

Hormones are chemical signals that influence cell’s activities. –produced by glands –travel through the circulatory system –affects cells with matching receptors target cell hormone receptor not a target cell bloodstream

There are steroid hormones and nonsteroid hormones. –Steroid hormones enter the cell. –Nonsteroid hormones do not enter the cell. Steroid hormone diffuses through the cell membrane Steroid hormone binds to a receptor within the cell. The hormone and receptor enter the nucleus and bind to DNA Steroid hormone causes DNA to make proteins. Nonsteroid hormone binds to receptor on the cell membrane. Receptor stimulates a second messenger with in the cell. Second messenger starts a series of chemical reactions in the cytoplasm. Second messenger reactions activate enzymes. Steroid hormone receptor nucleus DNA proteins Non-steroid hormone receptor second messenger Chemical reactions activated enzymes

Endocrine glands secrete hormones that act throughout the body. There are many glands located throughout the body. –Hormones travel through the bloodstream to cells with matching receptors. HYPOTHALAMUS PITUITARY THYROID THYMUS ADRENAL GLANDS PANCREAS FEMALE GONADS :OVARIES MALE GONADS : TESTES

The hypothalamus interacts with the nervous and endocrine systems. The hypothalamus is a gland found in the brain. –a structure of both the nervous and endocrine systems –produces releasing hormones, sent to pituitary gland The pituitary gland is found below the hypothalamus in the brain. –controls growth and water levels in blood –Also produces releasing hormones

Negative feedback loops are necessary for homeostasis. Feedback compares current conditions to set ranges. Negative feedback counteracts change. Negative Feedback Loop Holding breath, CO 2 levels rise, Control system forces exhale, inhale O 2 / CO 2 level returns to normal

Positive feedback increases change. –Torn vessel stimulates release of clotting factors –growth hormones stimulate cell division platelets fibrin white blood cell red blood cell blood vessel clot

Examples of feedback loops… Negative or Positive? 1.Your energy level decreases, stomach growls telling you need nutrition to get your energy levels back up. 2.The adrenaline rush you experience in dangerous situations. 3.You do sprints for an hour and you pass out. Your body is telling you your oxygen level is too low. NEGATIVE POSITIVE

Problem Solve #1 Box 2 Box 3 Box 4 Given Situation. Is it an example of negative or positive feedback? Explain Provide your own example of Negative Feedback Provide your own example of Positive Feedback Given Situation. Is it an example of negative or positive feedback? Explain

Problem Solve #1 Box 2 Box 3 Box 4 When contractions start during labor, the hormone oxytocin is released into the body and causes more contractions to allow a woman to give birth. It’s a hot day and you start to sweat. Provide your own example of Positive Feedback Provide your own example of Negative Feedback

Label the Brain/Neuron On the brain side, label and describe the function of the following: –Cerebellum, Frontal Lobe, Medulla Oblongata, Occipital Lobe, Parietal Lobe, Pituitary Gland, Pons, Spinal Cord, Temporal Lobe On the neuron, label and describe the function of the following: –Axon, axon terminal, cell body, dendrites, nucleus, Schwann cell