Chapter 9- Regulation Regulation: –T–The coordination and control of the life activities. –T–The internal environment must remain stable Homeostasis.
Nervous and Endocrine systems Stimulus: – Any change in the internal or external environment that causes a response. Response: – Reaction to a stimulus. Receptors: – Structures that are specialized to receive certain stimuli. Ex. Five senses.
Impulse: – An electrochemical charge generated along a neuron. The message! Effectors: – Parts of the body that respond. Ex. Muscles or glands.
The Neuron: – Aka nerve cell- receives and transmits impulses. – Composed of: Dendrites – Detect stimulus – Cell branches – Receives impulses Cyton – Cell body that contains the nucleus Axon – Branch of the cell that transmits impulses away from the cyton. Terminal branches – End of the axon – Secretes neurotransmitters (made by synaptic knobs)
Synapse: – Gap (space) between neurons – Neurotransmitters: – Chemicals secreted into the synapse by terminal branches. – Helps impulses jump the synapse. – Example acetylcholine, norepinephrine
Types of Neurons: Pathway is always sensory ->inter->motor Sensory neuron: – Carries impulse from receptors (5 senses) to brain and spinal cord (CNS). Interneuron: – Neuron found between sensory and motor neurons. – Located in brain and spinal cord. Motor neurons: – Carries impulse away from brain and spinal cord (CNS) to the effectors (muscles or glands).
The Central Nervous System -made up of the brain and spinal cord -Interneurons here
The Brain: Composed of millions of neurons – 3 divisions cerebrum: largest part of the brain area where sensory impulses are interpreted memory, thinking, and reasoning
cerebellum: – Balance and motor coordination medulla: – connects spinal cord to the brain. – Controls involuntary activity: breathing, heart beat, digestion
The Spinal Cord: Thick nerve located within the vertebrae. Protected by: vertebrae, meninges, cerebrospinal fluid. Connects directly with the base of the brain. Function: center for the reflex action – Reflexes: simple, involuntary, inborn patterns of behavior. – Reflex arc: pathway over which impulses travel. Stimulus receptor sensory neuron interneuron motor neuron effectors (RSIME!!)
The peripheral nervous system (PNS) Nerves outside CNS Carry impulses to other parts of the body. Breaks into somatic and autonomic – Somatic – voluntary activities Ex: batting a ball – Autonomic – involuntary activities Ex: breathing
Malfunctions of the Nervous System Cerebral Palsy May occur before/during /after birth. Damage to the motor areas of the brain. Difficulty in coordinating voluntary muscle Meningitis Inflammation of the meninges. It can be viral or bacterial.
Stroke Supply of blood to the brain is cut off. A clot or a hemorrhage can form. Brain damage and paralysis occurs. Polio Viral disease of the CNS. Results in paralysis.**Immunization- Salk and Sabin vaccine