Homeostasis

• Characteristics of Sensory neurons

  • Long, cell body in the middle of the Axon
• A voluntary response is a conscious action done on purpose because it is chosen
• The nervous system plays a key role in the coordination and regulation of body functions
• Characteristics of Relay neurons

  • Short, small cell body at one end with many dendrites branching off it
• An involuntary response is a quick and automatic reaction to a stimulus
• Nervous system function

  Receiving and processing information from the environment and from within the body, generating appropriate responses to maintain homeostasis
• Organisms require proper coordination between various organs and systems to work together to keep them alive
• An example of an involuntary response is a quick and automatic reaction to a stimulus
• Types of neurons

  • Sensory neurons (carry impulses from sense organs to the central nervous system)
  • Relay neurons (connect sensory and motor neurons inside the central nervous system)
  • Motor neurons (carry impulses from the central nervous system to effectors - muscles or glands)
• Meanings of stimulus, receptor, and effector

  • Stimulus (any change in the environment detected by Sensory neurons)
  • Receptor (structure that can detect a stimulus and generate an electrical impulse)
  • Effector (structure, often a muscle or gland, that responds to a signal from the nervous system resulting in a specific action or behavior)
• Characteristics of Motor neurons

  • Large cell body on one end, long dendrites branching off it
• Components of the mammalian nervous system

  • Central nervous system (brain and spinal cord)
  • Peripheral nervous system (all nerves in the body outside of the brain and spinal cord)
• An example of a voluntary response is deciding to raise your hand to answer a question in class
• Involuntary responses are very important for survival since voluntary responses take longer
• A reflex action is a means of automatically and rapidly integrating and coordinating stimuli with the responses of effectors (muscles and glands)
• Involuntary response


  Quick and automatic reaction to a stimulus that happens without us having to think about it
• Reflex arc

  1. Stimulus is detected by a receptor and converted into an electrical impulse

  2. Electrical impulse travels along the sensory neuron

  3. Passes on to the relay neuron which connects to the motor neuron

  4. Motor neuron carries the impulse to the effector

  5. Effector carries out the response
• An involuntary or reflex response is a fast and automatic reaction that doesn't involve the brain and helps protect the body from harm
• Voluntary response


  • Deciding to raise your hand to answer a question in class
• Synapse

  1. Impulse travels along the first neuron Neuron a and stimulates the release of neurotransmitter molecules from vesicles into the synaptic gap

  2. Neurotransmitter molecules diffuse across the gap

  3. Neurotransmitter molecules bind with receptor proteins on the next neuron

  4. Impulse is then stimulated in the next neuron
• Synapse


  • Neurons have vesicles containing neurotransmitter molecules
  • Neurotransmitters are chemical messengers
  • Messages are chemical instead of electrical at synapses
  • Synapses ensure that impulses travel in one direction only
• Reflex arc refers to the pathway that a nerve impulse follows in an involuntary or reflex response
• Involuntary response


  • When we touch something hot and our hand quickly pulls away before we even realize it's hot
• Testosterone and estrogen have roles in the menstrual cycle
• Adrenaline effects in stressful situations
• Main examples of homeostasis to know are body temperature and blood glucose
• Examples of hormones

  • Adrenal gland - adrenaline
  • Pancreas - insulin
  • Testes - testosterone
  • Ovaries - estrogen
• Pancreas secreting insulin

  Role in regulating blood glucose in the body
• Definition of hormones
• Mechanism of maintaining body temperature

  Heat loss when too hot, heat retention when too cold
• Main differences between nervous control and hormonal control
• Homeostasis

  Maintenance of a constant internal environment, control of internal conditions within set parameters
• Body temperature is maintained at 37 degrees
• Skin plays a role in maintaining body temperature
• Testosterone and estrogen


  • Important in developing male and female characteristics along with other specific functions
• Homeostasis is about keeping the entire environment inside our bodies constant
• Main differences between nervous control and hormonal control

  • Form of transmission, Pathway, Speed, Duration of effect
• Arteries and arterioles

  Arteries are larger blood vessels, arterioles are smaller branches that lead out into the skin
• Homeostasis is the mechanism where we lose heat when it gets too hot and retain heat when it gets too cold
• Dilation and vasoconstriction in arterioles

  Arterioles dilate to radiate more heat out when it's hot, constrict to retain heat when it's cold