6/26/16. Nucleus. Muscle fiber. Endomysium. Striations. Fig Fig Muscle fiber. Nucleus. A band. I band. Z disc

Transcription

1 6/26/16 Fig Nucleus Muscle fiber Endomysium Striations Ed Reschke 1 Fig Muscle fiber Nucleus A band I band Z disc Openings into transverse tubules Mitochondria Sarcoplasmic reticulum Triad: Terminal cisternae Transverse tubule Sarcolemma Sarcoplasm Myofibrils Myofilaments 2 1

2 Fig Tail Head (a) Myosin m olecule Myosin head (b) Thick filam ent Tr opom yosin Tr oponin com plex G actin (c) Thin filam ent Thick filam ent Thin filam ent Bare zone (d) Por tion of a sar com er e showing the over lap of thick and thin filaments 3 Fig Endomysium Linking proteins Basal lamina Sarcolemma Dystrophin Thin filament Thick filament Elastic filament 4 2

3 6/26/16 Fig M line Z disc H band A band I band 1 I band Individual myofibrils Nucleus Sar com er e (a) Sarcomere A band H band I band (b) Z disc Thick filament Thin filament Elastic filament I band M line Z disc a: Donald Fawcett/Visuals Unlimited 5 Table

4 Fig Spinal cord Motor neuron 1 Motor neuron 2 Neuromuscular junction Skeletal muscle fibers 7 Fig Motor ner ve fiber s Neuromuscular junction Muscle fiber s Motor ner ve fiber Myelin Schwann cell Synaptic knob (a) 100 µm Basal lamina Synaptic vesicles (containi ng ACh) Sarcolemma Synaptic cleft Nucleus Ach receptor Junctiona l folds Nucleus Mitochon dr ia Sarcoplasm Myofilam ent s (b) a: Victor B. Eichler 8 4

5 Table Fig Copy right Mc Graw-Hill Educ ation. Permiss ion required for reproduction or display. Nerve signal Mo to r nerve fiber Sarcolemma Ca 2+ enters synaptic knob Synaptic knob Synaptic vesicles ACh ACh re c e ptors Synaptic cleft 1 Arrival of nerve signal 2 Acetylcholine (ACh) release ACh ACh ACh receptor K + Sarcolemma Na + 3 Binding of ACh to receptor 4 Opening of ligand-regulated ion gate ; creation of end-plate potential K + Plasma membrane of synaptic knob Na + Voltage-re gulate d ion gates Sarcolemma 5 Opening of voltage -regulated ion gates; creation of action potentials 10 5

6 Fig Copy right Mc Graw-Hill Educ ation. Permiss ion required for reproduction or display. Terminal cisterna of SR T tubule T tubule Sarcoplasmic re ticulum Ca 2+ Ca 2+ 6 Action potentials propagated down T tubules 7 Calcium released from terminal cisternae Ca 2+ Troponin Tropomyosin Ac tin Thin filament Active sites Ca 2+ My o s i n 8 Binding of calcium 9 Shifting of tropomyosin; to troponin exposure of active sites on actin 11 Fig Copy right Mc Graw-Hill Educ ation. Permiss ion required for reproduction or display. Troponin Tropomyosin ADP Pi My o s i n 10 Hy drolys is of ATP to ADP + Pi ; activation and cocking of myosin head Cross -bridge: Ac tin My o s i n ADP ATP Pi 11 Formation of myosin actin cross-bridge 13 Binding of new ATP; breaking of cross-bridge ADP Pi Z Z 12 Power stroke; sliding of thin filament over thick filament I A I Appearance of contracting sarcomere 12 6

7 Fig Copy right Mc Graw-Hill Educ ation. Permiss ion required for reproduction or display. AChE ACh 14 Cessation of nervous stimulation and ACh release 15 ACh breakdown by acetylcholinesterase (AChE) Terminalcisterna of SR Ca 2+ Ca 2+ Ca 2+ ADP Ca 2+ Pi 17 Loss ofcalcium ions from troponin 16 Reabsorption of calcium ions by sarcoplasmic reticulum Tropomyosin ATP 18 Return of tropomyosin to position blockingactive sites of actin 13 Fig Optimum resting length ( µm) z z Overly contracted z z Overly stretched z z Relative tension generated upon stimulation Sarcomere length (µm) before stimulation 14 7

8 Fig Contraction phase Relaxation phase Muscle tension Latent period Time of stimulation Time 15 Fig Tension Stimulus voltage Threshold Stimuli to nerve Proportion of nerve fibers excited Maximum contraction Responses of muscle

9 Fig Muscle twitches Temporal summation and incomplete tetanus Complete (fused) tetanus Muscle tension Stimuli (a) Low stimulus frequency Stimuli (b) Physiologicially normal stimulus frequency Stimuli (c) Unnaturally high stimulus frequency 17 Fig Muscle develops tension but does not shorten No movement Muscle shortens, tension remains constant Movement Muscle lengthens while maintaining tension Movement (a) Isometric contraction (b) Isotonic concentric contraction (c) Isotonic eccentric contraction 18 9

10 Fig Length or Tension Muscle tension Muscle length Isometric phase Isotonic phase Time 19 Fig seconds Duration of exercise 40 seconds Repayment of oxygen debt Mode of ATP synthesis Aerobic respiration using oxygen from myoglobin Phosphagen system Glycogen lactic acid system (anaerobic fermentation) Aerobic respiration supported by cardiopulmonary function 20 10

11 Fig ADP ADP P i Myokinase AMP ATP Creatine phosphate ADP Pi Creatine Creatine kinase ATP 21 Table

12 Table Table

13 Fig Autonomic nerve fiber Neurotransmitter released Mitochondrion Varicosities Synaptic vesicle Single-unit smooth muscle 25 Fig Mucosa: Epithelium Lamina propria Muscularis mucosae Muscularis externa: Circular layer Longitudinal layer 26 13

14 Fig Autonomic nerve fibers Varicosities Gap junctions (a) Multiunit smooth muscle (b) Single-unit smooth muscle 27 Fig Intermediate filaments of cytoskeleton Actin filaments Dense bodies Myosin (b) Contracted smooth muscle cells (a) Relaxed smooth muscle cells 28 14

15 Page 431 INTEGUMENTARY SYSTEM Facial expr essions r esult fr om the action of m uscles on the skin. LYMPHATIC/IMMUNE SYSTEM Muscle contr actions aid flow of lym ph; exer cise elevates levels of im m une cells and antibodies in cir culation; excessive exer cise can inhibit im m unity. SKELETAL SYSTEM Muscles move and stabilize joints and pr oduce str esses that affect ossification, bone remodeling, and the shapes of bones. RESPIRATORY SYSTEM Muscle contr actions ventilate the lungs; muscles of the larynx and phar ynx r egulate air flow; CO2 gener ated by m uscular activity stim ulates r espir ation; abdom inal muscles produce pressure bursts of coughing and sneezing and aid in deep breathing. NERVOUS SYSTEM Muscles give expr ession to thoughts, em otions, and m otor com m ands that ar ise in the centr al ner vous system. URINARY SYSTEM A skeletal muscle sphincter retains urine in bladder until convenient for r elease; abdom inal and pelvic m uscles aid in com pr essing and em ptying bladder ; m uscles of pelvic floor suppor t bladder ; bulbospongiosus m uscle helps clear urine from male urethra. ENDOCRINE SYSTEM Skeletal muscles provide protective cover for som e endocr ine glands; muscle mass affects insulin sensitivity. DIGESTIVE SYSTEM Muscles enable chewing and swallowing; m uscles contr ol voluntar y aspect of defecation; abdom inal m uscles pr oduce vom iting; abdom inal and lum bar muscles protect digestive organs. CIRCULATORY SYSTEM Muscle contr actions affect blood flow in m any veins; exer cise stimulates gr owth of new blood vessels. REPRODUCTIVE SYSTEM Muscles ar e involved in sexual responses including erection and ejaculation; abdom inal and pelvic muscles aid in childbirth