Aim: What is a reflex arc? Do Now: How does the brain talk to the rest of the body? It is connected to ____________ which is connected to the body by __________
STIMULUS, RESPONSE, IMPULSE A change in the environment is ____________ Reaction to the change is _____________ A message through the nervous system is __________ A nerve cell is ____________
Yes, Mr. President, it is in the center…a part of your central nervous system…and so is your spinal cord!!!!
Nervous system is divided into 2 main parts: Central and Peripheral.
NEURON: Direction of impulse
Impulse traveling…it’s a relay race…
What happens if there is an emergency? Like, your finger is on fire? There is no time for the spinal cord to talk to the brain… If you remember, its your spinal cord that connects your body parts to the brain through_______________ So spinal cord has to take action… REFLEX ACTION
Reflex action Being an involuntary action or response, such as a sneeze, blink, or hiccup. Produced as an automatic response or reaction
Btw, who takes orders from the brain to move your effectors (I mean muscles and some glands? MOTOR NEURONS!
Knee jerk response...
Reflex arc
The reflex action
Can you give other examples of reflexes…
Peripheral Nervous System (2 Types) Somatic nervous system is for voluntary muscle control. These neurons control the skeletal muscles…. Also some spinal reflexes. EX = patellar reflex Autonomic nervous system is automatic. Control of heart rate, respiration, blood pressure, smooth muscle, etc. This has 2 separate divisions: sympathetic and parasympathetic Copy yes
An Overview of the (copy) Nervous System: Peripheral Nervous System Central Nervous System -Brain -Spinal Cord Sensory Neurons -carry messages towards spinal cord from sensory receptors Motor Neurons -carry signals away from CNS Somatic System: Voluntary Nerves --neurons control skeletal muscles Autonomic System: Visceral, Involuntary --heart, blood vessels, digestive organs, smooth muscle
Neurotransmitters… Acetylcholine: in skeletal muscles Norepinephrine and Epinephrine: respond to stress Dopamine & Serotonin: in the brain Enzymes break down neurotransmitters so neurons are not “over stimulated.” Ex. = cholinesterase (breaks down acetylcholine).
Neurotransmitters…
Neurotransmitters… After they have conveyed the impulse to the next neuron, what happens to the neurotransmitters?