-The process by which organisms maintain, control, and coordinate their internal environment with a constantly changing external environment -It is all of the activities that help to maintain an organism s
Homeostasis: the ability to maintain relatively constant internal conditions even though the external world changes continuously Within cells Within body
1.Nervous System nerve control (action/reaction) 2. Endocrine System- chemical control (hormones/receptors) -Process by which the product of a system shuts Down a system or limits its operation Ex: Home heating system Blood Sugar Level Shivering Menstrual Cycle
Homeostasis Maintained until another change occurs Change Detected/ System turned on System Limited or Shut down System Responds with production Homeostasis achieved
Stimulus- Changes that cause a response Ex: Light, sound Response- Reaction to a stimulus Neuron- Nerve cell that transmits impulses throughout the body Dendrites- detect stimulus Cyton-(Cell body) Contains nucleus and organelles
Axon- Connects cyton to terminal branches (elongated portion) Terminal Branches- end of neuron. Secretes neurotransmitters that allow impulses to jump over synapses Synapse- Gap between neurons Neurotransmitters-special chemical that allows impulses to jump synapses Impulse- An electrochemical charge that transmits information (the message)
Receptor Organ- Organs that receive stimuli (action) Ex: Eyes, ears, nose, skin, tongue Effectors- Muscles or glands that respond To stimuli (reaction) Dendrites Nucleus Terminal Branches Axon Synapse Myelin Sheath Cell body (Cyton)
How does the Nervous System maintain homeostasis? -by maintaining nerve control (action/reaction) What are the basic functional units of the human Nervous System? -Neurons -Nerves -Central Nervous System (CNS) -Peripheral Nervous System (PNS)
3 Types: Receive stimuli from the environment and transmit this information to the CNS for interpretation. Sensory receptor organs include: eyes, ears, nose, tongue, skin Transmit impulses from the CNS to the Effectors (muscles and glands) where an Appropriate response is initiated. Relay nerve impulses between sensory and motor neurons.
-A bundle of neurons all together (a tissue). They transmit impulses over long distances at high rates of speed.
Cell X is sending A message to Cell Y If a drug was being developed to block the action Of neurotransmitter A, what shape should the drug have?
-Impulse traveling -Neurons communicating
Pathway Example 1. Stimulus Heat from a stove 2. Receptor organ Nerves in skin of finger (any sense organ) 3. Sensory Neurons Carries impulses to the spinal cord 4. Interneurons Found in spinal cord. Connect Sensory to motor 5. Motor Neurons Carries impulses to effectors
6. Effector Muscles in arm 7. Response Pulling finger away from stove
What does the CNS consist of? -Brain -Spinal Cord What does the CNS do? -Relays messages -Processes and analyzes information ( Command Center )
How is the CNS protected? -The brain is protected by the SKULL -The spinal cord is protected by the VERTEBRAE How does the brain maintain homeostasis? -Regulates ALL activity -Stores memory and interprets what is happening
Division: Cerebrum Location: Top/Front (Largest part of brain) Function: -Regulates conscious, voluntary actions -Conditioned behaviors (habits) are centered here -Site of intelligence, learning, and judgment Examples: Thought, memory, reasoning, sense interpretation, speech
Division: Cerebellum Location: Rear of cranium Function: -Coordinates muscular activities and balance Examples: Coordination, walking, running, fine motor skills Division: Medulla Location: Base of brain Function: Coordinates involuntary activities Examples: Breathing, heart rate, blood pressure, peristalsis
Structure: Hypothalamus Location: Base of brain Function: -(Sensor) Gland that detects hunger, thirst, fatigue, anger, body temperature, blood sugar level Structure: Thalamus Location: Base of brain Function: -Recognizes messages from sense organs
Medulla
Right Brain -Controls left side of the body Processes: -Creativity, Artistic Ability -Patterns, Spatial awareness It Recognizes: -Faces -Places -Objects Left Brain -Controls right side of body Processes: -Analytical and Mathematical ability -Speech, time, sequences It Recognizes: -Letters -Words -Numbers
Why is the spinal cord part of the CNS? -It is continuous with the brain (Connected at the medulla) How does the spinal cord maintain homeostasis? -It is the center for reflex actions -Coordinates activity between brain and body structures Why is there fluid surrounding the Brain and Spinal Cord? -Shock absorbency and nourishment
INVOLUNTARY Sensory Receptor (found in sensory organ) Motor Neuron (sends impulse to effector) Sensory Neuron (receive stimulus; found in receptor) Interneuron (in spinal cord; interprets information) Effector (reaction)
How fast does this happen? -Completed BEFORE the cerebrum is even aware of the initial stimulus!!! What is the PNS? -consists of nerves extending throughout the body How does the PNS maintain homeostasis? -Receives information for and relays commands from the CNS Where is the PNS located? -Located outside of the CNS
-consists of nerves that control the VOLUNTARY muscles of the skeleton -Consists of nerves regulating INVOLUNTARY (automatic) functions (actions of glands and involuntary muscles)
Cerebral Palsy: -brain damage just before or after birth that affects a person s ability to control body movements and muscle coordination Caused by: Lack of oxygen to the brain Treatment: Most damage irreversible Victims usually undergo extensive physical therapy and in some cases surgery is required
Multiple Sclerosis: -Nerve disorder in which victims suffer from blurred vision, slurred speech, and shaky hands due to the fatty coverings of axons in brain or spinal cord being destroyed. Caused by: No definite known cause (linked to Genetics, environmental factors, and Geographical factors) Treatment: No cure
Alzheimer s Disease: -Victims suffer from memory loss, inability To think, speak, or care for oneself Caused by: Treatment: No known cause No cure. Usually fatal Parkinson s Disease: -Victims suffer from shaking, poor balance, and stiffening of muscles due to loss of function of neurons in brain Caused by: No known cause Treatment: No cure.