IUPUI

• originates in the spinal cord

  Autonomic NS and Somatic NS
• targets skeletal muscle

  Somatic NS
• under unconscious control

  Autonomic NS
• The parasympathetic branch of the ANS...

  - Arises from the brainstem and lower regions of the spinal cord.

  - Has long pre-ganglionic fibers.
• Which nerve has parasympathetic control of the heart?

  CN X (Vagus)
• Which tissues are only innervated by the Sympathetic NS?

  Liver and Kidney
• Why would the body have two different types of ACh receptors?

  Different receptors for ACh allows for different actions of ACh in different tissues.
• Poisoning of a person with mushrooms containing muscarine would be expected to have what effects?

  stimulus of target cells innervated by post-ganglionic parasympathetic fibers
• a2 adrenergic receptor

  inhibition of insulin, stimulating the release of glucagon, and contraction of the gastrointestinal tract
• a1 adrenergic receptor

  smooth muscle contraction, causes vasoconstriction
• b1 adrenergic receptors

  stimulation of salivary gland amylase secretion, increased kidney juxtaglomerular secretion of renin, lipolysis in adipose tissue, relaxation of the bladder detrusor muscle, tachycardia, increased force of heart muscle contraction, increased automaticity of the AV node
• b2 adrenergic receptor


  smooth muscle relaxation in uterus, decreased GI smooth muscle motility, relaxation of bladder detrusor muscle, bronchodilation, increased insulin release, dilation of hepatic and skeletal muscle arteries, increased liver glycogenolysis
• b3 adrenergic receptor

  increased adipocyte lipolysis increased thermogenesis, relaxation of bladder detrusor muscle
• ANS reflex


  Tissues can be innervated by both branches and they usually have opposite effects.
• The sensory receptors of special senses are located within a specific area of the body.


  true
• Which special senses use chemoreceptors?

  olfaction and gustation
• CN I


  olfaction
• CN II

  vision
• CN VII, IX, X

  gustation
• CN VIII

  hearing and equilibrium
• What happens when a person enters a brightly lit room?

  11-cis-retinal converts to 11-trans-retinal, photoreceptors decrease glutamate neurotransmitter secretion, light-on bipolar cells would activate
• When tip linked proteins are stretched, the hair cells...

  are depolarized
• Which of the special senses send information primarily through the limbic system instead of the thalamus?

  olfaction
• Skeletal muscle contractions with voluntary actions primary functions:

  - movement, support, and positioning of our body's skeleton

  - facilitation of interpersonal communication, including speaking, typing, writing, facial expressions, and gestures

  - temp regulation
• Smooth muscle contraction regulates

  - flow of material through the organs

  - flow of blood through the arteries and veins

  - flow of air into/out of the lungs
• skeletal movement

  created by contracting and pulling on tendons
• supportive structures

  maintain placement pf visceral organs and shield underlying tissues from injury
• posture

  contract to hold the body still
• communication

  speaking, typing, writing, facial expressions, and gestures
• regulation of flow

  contractions change the tube diameter
• generate blood pressure


  squeeze on the blood in a hollow organ
• Do muscles only push, only pull, or both?

  Only pull
• A cross-bridge forms when what occurs?

  - The myosin heads bind to the attachment sites on the actin myofilament

  - Actin and myosin bind to form a physical link
• Steps and events at the neuromuscular junction (NMJ)

  1. an action potential propagates along the axon of an A-motor neuron to the presynaptic axon terminal

  2. Depolarization of the axon terminal causes voltage-dependent calcium channels to open and Ca2+ ions flow from the extracellular fluid into the presynaptic neuron's cytosol.

  3. The influx of Ca2+ causes neurotransmitters containing vesicles to dock and fuse to the presynaptic neuron's cell membrane.

  4. Vesicle membrane fusion with the neuronal plasma membrane leads to exocytosis of the acetylcholine into the synaptic cleft.

  5. Acetylcholine diffuses throughout the synaptic cleft and binds to the nicotinic acetylcholine receptors in the sarcolemma of the motor end-plate.

  6. As acetylcholine unbinds from its receptor, it is degraded by the enzyme acetylcholinesterase, causing termination of the excitatory signal.

  7. The choline can be then recycled back into the presynaptic terminal, where it is used to synthesize new acetylcholine molecules.
• Why is there a smaller muscle fiber to motor neuron ratio for muscles responsible for precision?

  Because control of the individual muscle fibers increases. Specifically, with a smaller number of muscle fibers per motor unit, a person's ability to control the amount of force exerted increases, making the movement more precise.
• All innervated muscle fibers of a motor unit fully contract when stimulated beyond threshold due to what?

  when a motor neuron is stimulated, all of the fibers it innervates are activated
• events that occur in a cross-bridge cycle to contract a skeletal muscle:

  1. Initiation

  2. Power Stroke

  3. Detachment

  4. Relaxation
• tetanic contraction


  sustained muscle contraction in face of high frequency of activation
• fused tetanus


  no relaxation in face of a high frequency of muscle stimulation
• unfused tetanus


  partial relaxation in face of a high frequency of muscle stimulation