Notes: Nervous System KEY CONCEPT #1 The and the provide the means by which organ systems. The body s communication systems help maintain homeostasis. A stimulus is. Responses. The nervous and endocrine systems respond to stimuli. The endocrine system controls. The nervous system controls. The nervous and endocrine systems have different methods and rates of communication. The nervous system is made up of works uses signals that move through cells divided into and The endocrine system is made up of and works more. only signals in the form of signals move through KEY CONCEPT #2 The nervous system is composed of Neurons are highly specialized cells. A neuron has three major parts. 1. : 2. : 3. : P a g e 1
Neurons have other structures to transmit signals. : makes up the axon terminal (bouton): synapse: Neurons receive and transmit signals. The axons of a neuron have an. This means that the neuron will fire the signal or not. There s no in-between. This is determined by meeting a certain Resting potential is usually In order for an action potential to be fired it must reach a threshold of about These different voltages are determined by that move of the neuron P a g e 2
Resting potential means. Details: Overall charge: outside; inside An action potential is. It is generated by a. channels open causing them to rush the cell Membrane is ( outside; inside) As the action potential moves along the neuron, channels open causing them to rush of the cell This is (positive outside; negative inside) P a g e 3
A chemical signal passes between neurons. Impulse reaches terminal rushes into the presynaptic neuron causing the synaptic to fuse with the from presynaptic neuron are released into synapse. that next cell bind to on Types of neurotransmitters like and (GABA) like (epinephrine), noradrenalin (norepinephrine), and like like and Types of Neuron Communication The signal that is passed on can be or depending of the type of found on the An (EPSP) carries out an action potential by up the An (IPSP) does not carry out an action potential by up. This makes the outside super positive and the inside super negative. This is called and the charge is much less than resting potential (about 90mV) P a g e 4
KEY CONCEPT #3 The central nervous system information, and the peripheral nervous system information. The nervous system s two parts work together. The CNS includes the and. The PNS includes four systems of. The CNS and PNS pass signals between one another. The CNS processes information. The brain. Made up of three parts: controls thought, movement, emotion allows for balance controls basic life functions The brain stem Has three parts: controls some reflexes regulates breathing controls heart function, swallowing, coughing, aggression. The spinal cord. Involves a: which receives the info and sends it to spinal cord P a g e 5
interprets the info and relays the impulse to the and causes an action/response does not involve the The PNS links the CNS to muscles and other organs. The nervous system regulates like The nervous system controls like. nervous system: controls Details: heart rate nervous system: Details: conserves ; heart rate KEY CONCEPT #4 The detect the internal and external environment stimuli. The senses help to maintain homeostasis. Senses, and send it to the. Nervous system to stimuli. Pupils when light enters the eyes. form when air touches skin. P a g e 6
Types of Sensory (receptors) Neurons : detects pressure, touch stretch, motion, and vibration : detects visible light : detects chemicals in the air : responds to temperature differences : detects pain The senses detect physical and chemical stimuli. The contributes to. controls the of the which controls the that enters the eye Photoreceptors located within the sense light. Two photoreceptors work together: : detect light : detect color Structure of the Eye P a g e 7
The contributes to. mechanoreceptors called in response to Interpreting sound (auricle) collect the sound Sound waves travel down the Sound waves hit the (eardrum) causing it to vibrate Vibrations are carried along the tiny bones in the ear called the,, and. Eventually, the vibrations reach the which bends the hair cells When the are, an is sent down the. Taste and smell use. Taste uses, and smell uses. Chemoreceptors detect dissolved in fluid. The skin senses. detect. detect. detect. KEY CONCEPT #5 The system produces that affect growth, development, and homeostasis. Hormones influence a cell s activities by entering the cell or binding to its membrane. are organs of the endocrine system. are chemical signals that influence cell s activities. produced by glands P a g e 8
travel through the affects with matching There are (lipid) hormones and (protein) hormones. hormones the cell. hormones the cell. Steroid hormone diffuses through the cell membrane Nonsteroid hormone binds to receptor on the cell membrane. Steroid hormone binds to a receptor within the cell. Receptor stimulates a second messenger with in the cell. The hormone and receptor enter the nucleus and bind to DNA Second messenger starts a series of chemical reactions in the cytoplasm. Steroid hormone causes DNA to make proteins. Second messenger reactions activate 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 P a g e 9
The hypothalamus interacts with the nervous and endocrine systems. The is a gland found in the brain. a structure of both the and systems produces releasing hormones, sent to The is found below the hypothalamus in the brain. controls and in blood produces sent throughout the body o stimulate other glands to produce hormones. o allow glands to with one another o are used in Hormonal imbalances can cause severe illness. Abnormal hormone levels affect. Hormonal imbalances might be treated with or., a pituitary tumor, or some can make the pituitary and indirectly cause problems. P a g e 10