29.2 Neurons KEY CONCEPT The nervous system is composed of highly specialized cells.
. The nervous system works quickly, using chemical and electrical signals. interconnected network of cells signals move through cells divided into central nervous system (CNS)- brain and spinal cord and peripheral nervous system (PNS)- nerves throughout the body. nerves spinal chord
29.2 Neurons Neurons are highly specialized cells. A neuron has three parts. cell body has nucleus and organelles 1 Cell body
Neurons are highly specialized cells. A neuron has three parts. cell body has nucleus and organelles dendrites receive impulses 2 dendrites
Neurons are highly specialized cells. A neuron has three parts. cell body has nucleus and organelles dendrites receive impulses axon carries impulses: caused by sodium and potassium concentrations. 3 axon
29.2 Neurons Neurons have other structures to transmit signals. Schwann cell: myelin sheath, speeds nerve impulse
29.2 Neurons Neurons have other structures to transmit signals. Schwann cell Synapse: where 2 nerve cells meet synapse
29.2 Neurons Neurons have other structures to transmit signals. Schwann cell synapse Terminal: end of one nerve cell. axon terminal
29.2 Neurons A chemical signal passes between neurons. Impulse reaches terminal. impulse
29.2 Neurons A chemical signal passes between neurons. Impulse reaches terminal. impulse
29.2 Neurons A chemical signal passes between neurons. Impulse reaches terminal. Neurotransmitters released into synapse. impulse synapse neurotransmitter vesicles receptor
29.2 Neurons A chemical signal passes between neurons. Impulse reaches terminal. Neurotransmitters released into synapse. Neurotransmitters stimulate next cell. impulse synapse neurotransmitter vesicles receptor
KEY CONCEPT The senses detect the internal and external environments.
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.
The senses detect physical and chemical stimuli. The eye contributes to vision. Photoreceptors sense light. Two photoreceptors work together: rod cells and cone cells.
The ear contributes to hearing. mechanoreceptors called hair cells bend in response to vibrations
Taste and smell use chemoreceptors. Taste uses tongue, and smell uses nose. Chemoreceptors detect chemicals dissolved in fluid.
The skin senses touch. Mechanoreceptors detect pressure. Pain receptors detect damaged tissue. Thermoreceptors detect temperature. pain receptor light pressure receptor hair follicle heavy pressure receptor
KEY CONCEPT The central nervous system interprets information, and the peripheral nervous system gathers and transmits information.
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.
The CNS and PNS pass signals between one another. Sensory receptor(eye) generates impulse. PNS passes impulse to CNS(brain). CNS interprets impulse. CNS passes impulse to PNS. PNS stimulates a response(hit baseball).
The CNS processes information. The brain has three parts. cerebrum controls thought, movement, emotion cerebellum allows for balance brain stem controls basic life functions Brain stem midbrain pons medulla oblongata
Different lobes of the cerebrum are related to different functions: Frontalconscious thought Parietalcoordination of all the senses Temporalhearing and smell Occipital-vision
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. The somatic nervous system regulates voluntary movements. The autonomic nervous system controls involuntary, functions sympathetic nervous system: fight vs. flight parasympathetic nervous system: calms the body, conserves energy