Regulatory Systems: Nervous and Endocrine Systems. Function of Regulation Systems:. regulate the activities of the other systems to make sure homeostasis is maintained
regulate the activities of the other systems to make sure homeostasis is maintained
(homeostasis: keeping the internal environment of the body constant; for example, body temperature, blood pressure)
Uses Electrical signals (impulses) along nerves
Chemical signals (neurotransmitters) to pass the impulse to the next cell
Hormones made in glands
The bloodstream for transmission
Integrate the Input
Send out motor commands
The impulse is transmitted:
Sensory neuronssense stimuli caused by changes in the internal or external environment
Interneurons integrate signals from different parts of the nervous system
Motor neuronstransmit signals to muscles and glands
Glands secrete substances
Channel proteins maintain the polarity
This is called its Resting Potential
The transmission of a nerve impulse is rapid and self-propagating (like dominoes)
The major players:
The nerve impulse is transmitted along the neuron by reversing the negative charge along the membrane
Inside becomes more positive than outside
This is called the action potential
Sodium channels open in part of the membrane and Na+ ions enter the cell
Cell is more negative outside
As Sodium channels close Potassium channels open and K+ ions leave the cell
Cell is more positive outside
Sodium channels open in the area next to the original action potential, passing the impulse along
Sodium-Potassium Pump moves 3 sodium ions out of the cell and 2 potassium ions inside the cell, restoring the original positions of ions
Sodium – Potassium Pump is Active transport:
Moving substances across membrane from lower to higher concentration requires cell to expend energy.
Transmission of the action potential in myelated axons (faster than in non myelated axons)
Until the position of the ions is restored, the nerve can not carry another impulse
All or None Principle:
A nerve cell will either fire or not fire – once the impulse begins, it will continue down the cell
Impulse is the same intensity each time
Different strengths of stimuli can be detected by:
Passing the impulse to the next cell
Synapse:gap in between an axon terminal and a dendrite
The neurotransmitters are released into the synapse
At the end of the terminal branches are vesicles with neurotransmitters
1. Nerve impulse reaches axon end
2. Neurotransmitter (NT) released into synapse (exocytosis)
3. Neurotransmitter diffuses across synapse
4. Neurotransmitter binds to receptors in the cell membrane of the next neuron
5. Impulse generated at the next neuron.
Two main components:
(1) Central Nervous System (CNS): Brain + Spinal Cord
speech, vision, hearing, thought
Sensory inputhunger, thirst, temperature
Balance, posture, coordination
Heart beat, breathing
Treatment for a wide range of mental illnesses including schizophrenia, clinical depression, and various anxiety disorders.
Phineas Gage (1848)
Functions:Carry sensory impulses from receptors to CNS
Carry motor impulses from CNS to muscles and glands.
Composed of nerves
(bundle of axons)
The bundled axons make up the nerves of the PNS
Cell bodies of neurons are found in the CNS or in ganglia present in the PNS
(ganglion = collection of cell bodies)
Divided into Two main Sections:
Hammer - (malleus)
passes vibrations from the eardrum to the anvil.
Anvil - (incus)
passes vibrations from the hammer to the stirrup
Stirrup - (stapes)
U-shaped bone that passes vibrations from the stirrup to the cochlea.
smallest bone in the human body.
To cochlear nerve
Air pressure waves in the ear canal (sound energy) causes...
Ear drum motion (vibrational energy), which causes...
Motion of the ossicles (vibrational energy), which causes...
Inner ear fluid pressure waves (vibrational energy), which causes…
Nerve impulses within the cochlea, which are then carried via a series of nerve connections to the portion of the brain that perceives "sound," the auditory cortex (electrochemical energy.)