HNF 462 1st Edition Lecture 18Outline of Last LectureI. Osmotic PressureII. Maintenance of Fluid Balancea. Hydrostatic Pressureb. ISF Colloid Osmotic Pressurec. Negative ISF Hydrostatic Pressured. Plasma Osmotic PressureIII. Regulation of Extracellular Water Osmolarity and Volumea. Renin-Angiotensin-Aldosterone b. Atrial Natriuretic PeptideIV. HypertensionV. Water, Electrolytes, and Muscle FunctionOutline of Current LectureI. Second MessengersII. Calcium as a Second MessengerIII. Muscle ContractionIV. Other Functions of CalciumV. Muscle RelaxationVI. Effects of Physical Activity and Weight Loss on Diabetic PatientsVII. MyoglobinVIII. Function of MyoglobinCurrent Lecture: Second Messengers and Muscle Contraction1. Second Messengersa. Small molecules that transmit signals from a receptor on the cell’s surface to a target inside the cellThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.b. Ex: cAMP, Ca++2. Calcium as a Second Messengera. Stimulus on cell surface generate calcium mobilizing signalb. ON mechanism triggers calcium releasec. Rising calcium concentration triggers Ca-sensitive processes3. Muscle Contractiona. Motor neuron releases acetylcholine into synaptic clefb. Action potential in muscle cellsc. Action potential travels down T-tubulesd. T-tubules release Ca++ from sarcoplasmic reticulume. Calcium binds to troponin, which moves tropomyosin from blocking binding sites on actinf. Myosin binds to acting. ATP generates power stroke = muscle contraction4. Other Functions of Calciuma. Activation of glycogenolysis: increased calcium levels can activate phosphorylation ofPKA without glucagon presentb. Activation of PDH by activating pyruvate dehydrogenase phosphatase to dephosphorylate PDH-P5. Muscle Relaxationa. Absence of Calcium will move troponin/tropomyosin back to blocking position on actin6. Effects of Physical Activity and Weight Loss on Diabetic Patientsa. Weight loss and exercise will increase number of mitochondria in muscle tissueb. Decrease accumulation of fat tissue in skeletal muscle (accumulation of fat can causeinsulin resistance in muscle cells)7. Myoglobina. In muscle cellsb. Made of one globin protein and one heme (contains one iron ion)c. One oxygen can bind to one myoglobin: myoglobin has a higher affinity that hemoglobind. Transports oxygen from the blood to the muscle8. Function of Myoglobina. Facilitation of intracellular oxygen diffusionb. Expressed in heart muscle and skeletal musclec. Can store oxygen in muscle so during hypoxia or anoxia, muscle can release oxygend. Severe iron deficiency reduces myoglobin in
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