Regulation

Chapter 9- Regulation

• Regulation:–The coordination and control of

the life activities.–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.

Neuron

Neurons

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 receptorsensory neuroninterneuronmotor neuroneffectors (RSIME!!)

• YouTube - Central Nervous System, Reflex Arc

http://en.wikipedia.org/wiki/Image:Medulla_oblongata.jpg

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