4 KEY CONCEPT The nervous system and the endocrine system provide the means by which organ systems communicate.
5 The body’s communication systems help maintain homeostasis. A stimulus causes a response.Responses can be chemical, cellular, or behavioral.The nervous and endocrine systems respond to stimuli.
6 The nervous system controls thoughts, movement, and emotion. The endocrine system controls growth, development, and digestion.
7 The nervous and endocrine systems have different methods and rates of communication. The nervous system works quickly, using chemical and electrical signals.interconnected network of cellssignals move through cellsdivided into central nervous system (CNS) and peripheral nervous system (PNS)spinal chordnerves
8 The endocrine system works more slowly. only chemical signalssignals move through bloodstreamphysically unconnected organstarget cellhormonebloodstreamreceptornot a target cell
9 Neurons are highly specialized cells. A neuron has three parts.cell body has nucleus and organelles1Cell body
10 Neurons are highly specialized cells. A neuron has three parts.cell body has nucleus and organellesdendrites receive impulses2dendrites
11 Neurons are highly specialized cells. A neuron has three parts.cell body has nucleus and organellesdendrites receive impulsesaxon carries impulses3axon
12 Neurons have other structures to transmit signals. Schwann cell
13 Neurons have other structures to transmit signals. Schwann cellsynapsesynapse
14 Neurons have other structures to transmit signals. Schwann cellsynapseterminalaxon terminal
15 Neurons receive and transmit signals. Resting potential means no signal is being transmitted.more Na+ outside of cellmore K+ inside of cell
16 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.area of detail
17 A chemical signal passes between neurons. Impulse reaches terminal.impulse
18 A chemical signal passes between neurons. Impulse reaches terminal.impulse
19 A chemical signal passes between neurons. Impulse reaches terminal.Neurotransmitters released into synapse.synapseimpulseneurotransmittervesiclesreceptor
20 A chemical signal passes between neurons. Impulse reaches terminal.Neurotransmitters released into synapse.Neurotransmitters stimulate next cell.synapseimpulseneurotransmittervesiclesreceptor
22 KEY CONCEPT The senses detect the internal and external environments.
23 The senses help to maintain homeostasis. Senses gather stimuli, and send it to the nervous system.Nervous system responds to stimuli.Pupils shrink when too much light enters the eyes.Goose bumps when cold air touches skin.
24 The senses detect physical and chemical stimuli. The eye contributes to vision.Photoreceptors sense light.Two photoreceptors work together: rod cells and cone cells.
25 The ear contributes to hearing. mechanoreceptors called hair cellsbend in response to vibrations
26 Taste and smell use chemoreceptors. Taste uses tongue, and smell uses nose.Chemoreceptors detect chemicals dissolved in fluid.
28 KEY CONCEPT The central nervous system interprets information, and the peripheral nervous system gathers and transmits information.
29 The nervous system’s two parts work together. The CNS includes the brain, brain stem, and spinal cord.The PNS includes four systems of nerves.
30 The CNS and PNS pass signals between one another. Sensory receptor generates impulse.PNS passes impulse to CNS.CNS interprets impulse.CNS passes impulse to PNS.PNS stimulates a response.
31 The CNS processes information. The brain has three parts.cerebrum controls thought, movement, emotioncerebellum allows for balancebrain stem controls basic life functionsBrain stemmidbrainponsmedulla oblongata
32 The brain stem has three parts. midbrain controls some reflexespons regulates breathingmedulla oblongata controls heart function, swallowing, coughingmidbrainponsmedulla oblongata
33 The spinal cord controls reflexes. sensory neuron sends impulse to spinal cordspinal cord directs impulse to motor neurondoes not involve the braininterneuronmotor neuronssensory neuron
34 The PNS links the CNS to muscles and other organs. The somatic nervous system regulates voluntary movements.The autonomic nervous system controls involuntary, functionssympathetic nervous system: “fight vs. flight”parasympathetic nervous system: calms the body, conserves energy
35 KEY CONCEPT Scientists study the functions and chemistry of the brain.
36 New techniques improve our understanding of the brain. Today, scientists study the brain without surgery.
37 There are three common technologies. CT uses x-rays to view structure.MRI uses magnetic fields and radio waves to view structure.PET detects activity, where glucose is used, in the brain.
38 Changes in brain chemistry can cause illness. Different neurotransmitters relate to different functions.synapseNormalreceptorneurotransmittersome stimulate impulsessome prevent impulses
39 Abnormal levels of neurotransmitter can cause illness. schizophreniadepressionNormalSchizophrenicDepressed
40 Drugs alter brain chemistry. 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 receptorssensitization: less neurotransmitter leads to more receptors.When the amount of neurotransmitter becomes abnormal, the adjacent neuron adapts.
41 Stimulants cause more action potentials may increase neurotransmitter in synapsemay decrease removal of neurotransmitter in synapsecocaineneurotransmittersynapse
42 Depressants cause fewer action potentials. may produce neurotransmitter that prevent impulsesmay slow release of neurotransmitter that generates impulses
43 KEY CONCEPT The endocrine system produces hormones that affect growth, development, and homeostasis.
44 Hormones influence a cell’s activities by entering the cell or binding to its membrane. Glands are organs of the endocrine system.
45 Hormones are chemical signals that influence cell’s activities. produced by glandstravel through the circulatory systemaffects cells with matching receptorstarget cellhormonebloodstreamreceptornot a target cell
46 There are steroid hormones and nonsteroid hormones. Steroid hormones enter the cell.Nonsteroid hormones do not enter the cell.Steroid hormoneNon-steroid hormoneSteroid hormone diffuses through the cell membraneSteroid hormone binds to a receptor within the cell.The hormone and receptor enter the nucleus and bind to DNASteroid 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.receptorreceptorsecond messengernucleusChemical reactionsDNAactivated enzymesproteins
47 Endocrine glands secrete hormones that act throughout the body. There are many glands located throughout the body.HYPOTHALAMUSPITUITARYTHYROIDTHYMUSADRENAL GLANDSPANCREASFEMALE GONADS :OVARIESMALE GONADS : TESTESHormones travel through the bloodstream to cells with matching receptors.
48 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 systemsproduces releasing hormones, sent to pituitary glandThe pituitary gland is found below the hypothalamus in the brain.controls growth and water levels in bloodproduces releasing hormones sent throughout the body
49 Releasing hormones stimulate other glands to produce hormones. allow glands to communicate with one anotherare used in temperature regulation
50 Hormonal imbalances can cause severe illness. Abnormal hormone levels affect homeostasis.Hormonal imbalances might be treated with surgery or medicine.Steroids, a pituitary tumor, or some prescription drugs can make the pituitary overactive and indirectly cause problems.