How is ATP used during muscle contraction o Used to break the bond between

How is atp used during muscle contraction o used to

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How is ATP used during muscle contraction: o Used to break the bond between actin and myosin o Used to fuel the pumps that move calcium back into the sarcoplasmic reticulum ( SR) after contraction. o Used to energize the myosin heads and put them into position. o ** ATP is needed for the power stroke but not for the binding itself. Troponin: Calcium binds causing shape change that moves tropomyosin Troponin complex:
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PCB STUDY GUIDE 29 o Troponin I Inhibits binding of myosin o Troponin T binds to tropomyosin o Troponin C binds to calcium (binding site/receptor for calcium) **Tropomyosin wraps around actin filaments. Transverse tubules: Voltage-gated calcium channels open Sarcoplasmic reticulum: Calcium release channels open Neuromuscular junction: Site where a motor neuron stimulates a muscle fiber. Digestive system Large molecules = polymer Subunits of large molecules = monomer Disassembly line: 1) Motility: Is the movement of food through the alimentary tract through the process of: Ingestion = taking food into the mouth Mastication = Chewing breaks down food into smaller pieces for deglutition and mixes it with saliva Deglutition = Swallowing food Peristalsis = rhythmic wavelike contractions Segmentation = mixing contractions in different segments **peristalsis and segmentation together move food throught the alimentary tract. 2) Secretion: Release of cell products ( enzymes, hormone) that contribute to the digestive process. Exocrine secretion: Water, hydrochloric acid (HCl), bicarbonate and many digestive enzymes are secreted into the alimentary tract. Endocrine secretion: The stomach and small intestine secretes a number of hormones that help regulate the digestive system. 3) Digestion: Process of converting food into molecules that can be absorbed through the intestine into the blood. 4) Absorption: Is the transport of molecules across epithelial membranes into the body fluids. 5) Storage and elimination: Temporary storage and subsequent elimination of undigested food molecules 6) Immune barrier
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PCB STUDY GUIDE 30 **Digestive enzymes direct reactions which may break covalent bonds in both food and water molecules ** The term Viscera is frequently used to refer to abdominal organs of digestion, and organs in the thoracic and abdominal cavities. The GI tract is composed of 4 layers or tunics. 1) Mucosa: Lines the lumen of the alimentary tract, is the absorptive and major secretory layer, which is also responsible for protection. 2) Submucosa: Is a highly vascular layer of connective tissue that serves the mucosa. The components of the submucosa are supported by connective tissue, located between muscularis mucosa and muscularis externa. Submucosal plexus or Meissner’s plexus: o Provides a nerve supply to the muscularis mucosa of the small and large intestines.
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