Excretory and Musculature Systems Flashcards
The movement of solutes from blood to filtrate at Bowman’s capsule. This direction and rate is measured by Starling Forces.
Filtration
Accounts for the hydrostatic and oncotic pressure differentials between the glomerulus and Bowman’s space.
Starling Forces
The movement of solutes from blood to filtrate anywhere other than Bownman’s capsule.
Secretion
The movement of solutes from filtrate to blood.
Reabsorption
The site of bulk reabsorption of: - glucose - AA - soluble vitamins - salt and water Also the site of secretion for: - H+ - K+ - NH3+ - urea
Proximal Convoluted Tubule (PCT)
Permeable to water but NOT salt; therefore, as the filtrate moves into more osmoticlaly concentrated renal medulla, water is reabsorbed from the filtrate.
Descending Loop of Henle
Permeable to salt but NOT water; therefore, salt is reabsorbed both passively and actively.
Asending Loop of Henle
Responsive to aldoesterone and is a site of salt reabsorption and waste product excretion (like PCT).
Distal Convoluted Tubule
Responsive to both aldosterone and ADH and has variable permeability, which allows reabsorption of the right amount of water depending on the body’s needs.
Collecting Duct
A steroid hormone regulated by the renin-angiotensin-aldosterone system (stimulated with low BP/BV) that increases sodium reabsorption in the distal convoluted tubule and collecting duct, thereby increasing water reabsorption.
Aldosterone
A peptide hormone that is release stimulated by low blood volume and high blood osmolarity. Increases the permeability of the collecting duct to water, increasing water reabsorption (thus, increased BV/BP and decreased BO).
Antidiuretic Hormone (ADH/Vasopressin)
Three major layers of the skin?
- Hypodermis (Subcutaneous Layer)
- Dermis
- Epidermis
What are the five layers of the epidermis?
- Stratum (B)asale - Deepest
- Stratum (S)pinosum
- Stratum (G)ranulosum
- Stratum (L)ucidum
- Stratum (C)orneum - Superficial
What protect the skin from DNA damage caused by ultraviolet radiation?
Melanin (produced by melanocytes)
Special macrophages that serve as antigen-presenting cells in the skin.
Langerhans Cells
Basic contractile unit of striated muscle.
Sarcomere
What is mostly in thick filaments?
Myosin
What is mostly in thin filaments?
Actin
Are found in thin filaments and regulate actin-myosin interactions.
Troponin and Tropomyosin
A muscle cell or muscle fiber that contains many myofibrils.
Myocyte
Sarcomeres attach end to end to become?
Myofibrils
Explain the mechanism of muscle contraction.
- Motor neurons release ACh that binds to the receptors on the sarcolemma, causing depolarization (releasing Ca2+).
- Ca2+ binds to troponin > myosin binds to actin.
- Powerstroke occurs and the sarcomere contracts; ADP and Pi dissassociate from myosin.
- New ATP binds to myosin and this causes the myosin to detach from actin; hydrolysis of ATP to ADP and Pi causes recocking of the myosin head.
A heme containing protein that is a muscular oxygen reserve.
Myoglobin
Provides strength and density (part of bone).
Compact Bone
