Ch. 6 & 10 Flashcards
Which bone marrow type, red bone marrow or yellow bone marrow, engages in hemopoiesis?
Red bone marrow.
What are the primary products of hemopoiesis?
RBCs, WBCs, Platelets.
Contrast the functions of osteoblasts and osteoclasts.
Osteoblasts = Build up
Osteoclasts = Break down
What is the other more common name of the epiphyseal plate and what is it’s basic function?
Epiphyseal Plate = Growth Plate
Allows diaphysis of bone to lengthen.
What is the physiologic negative feedback signal to turn off the sequence that leads to the production and release of PTH?
Increased levels of Calcium. (Hypercalcemia)
Explain the main actions of PTH on the osteoclasts, the kidneys, and on calcitriol (i.e. activated vitamin D) formation by the kidneys.
During Hypocalcemia, Parathyroid releases PTH.
PTH stimulates Osteoclast activity.
Release of Ca back into bloodstream occurs.
Bone resorption occurs.
PTH also stimulates Kidneys to form stored Calcitriol.
Calcitriol increases resorption of Ca into GI Tract.
Two basic mechanisms of drugs used to treat osteoporosis:
Anti-resorptive drugs: Slow down progression of bone loss.
Bone-building drugs: Promote increasing bone mass.
Are mature skeletal muscle cells capable of cell division?
Yes, via Satellite Cells.
What is the difference in Hypertrophy and Hyperplasia?
Hypertrophy = Increase size of muscle cells.
Hyperplasia = Increase # of muscle cells.
Describe the Excitation-Coupling process.
Nerve impulse at NMJ initiate arrival of muscle action potential.
Triggers release of Ca++ ions stored in SR.
3-4 hrs after death, cross bridges are formed by leaking Ca ions into cytosol, linking Myosin/Actin proteins.
With no ATP to reverse cross bridges, Rigor Mortis occurs.
What does Botulinum Toxin do to prevent skeletal muscles from working normally?
It blocks release of ACh from nerve part of NMJ.
What does Curare do to prevent skeletal muscles from working normally?
It blocks receptors from receiving ACh at muscle part of NMJ.
Explain why a drug that works as neostigmine does might be prescribed to help myasthenia gravis, which destroys ACh receptors on skeletal muscles at NMJ’s.
Neostigmine acts as inhibitors of Acetylcholinesterase, which limits breakdown of ACh.
This raises level of ACh to bind with receptors that are still functioning.
Define Isotonic contraction.
Muscle shortens/lengthens.
Define Isometric contraction.
Muscle tenses, but not shortens/lengthens.
