Lecture Notes for General Biology BI 101 - Skeletal and Muscular Systems


I Study of Skeletal Systems

	A) Current Issues - Bone and Joint Pathology
		1) Rheumatoid arthritis - autoimmune disease,
			affects smaller joints (e.g., hands)
		2) Osteosarcoma - malignant bone tumor
		3) Osteoporosis - porous bones
		4) Scoliosis - lateral bending of the vertebral column
		5) Gout - deposition of sodium urate crystals
		6) Osteoarthritis - wear and tear arthritis, major joints (e.g., knees)
	B) Function
		1) Support
		2) Movement
		3) Protection
		4) Mineral reserve (in vertebrates)
		5) Blood cell production (in vertebrates)
	C) Types of Skeletons
		1) Hydrostatic - water-filled skeleton
			a) Unicellular organisms and starfish
		2) Exoskeleton - chitin (carbohydrates)
			a) arthropods (insects and lobsters)
		3) Endoskeleton - vertebrates
	D) Human Skeleton - generic example of a vertebrate
		1) Axial skeleton = skull, vertebral column
		2) Appendicular skeleton
			a) Forelimb
				1) girdle = scapula, clavicle
				2) humerus, radius, ulna, carpals, metacarpals, 
					digits=phalanges
			b) Hindlimb
				1) girdle = ilium, ischium and pubis
				2) femur, tibia, fibula, tarsals, metatarsals, 
					digits=phalanges
		3) joints where bones meet
			suture
			hinge
			ball and socket
	E) Study of Adaptation - Feeding, Skulls and Teeth
		Carnivores - canines, carnassial molars
			Canids (Dogs)
				Coyote
			Felids (Cats)
				Lynx
				Bobcat
				Cougar
			Ursids (Bears)
				Black Bear
			Mustelids and other Predators
				Wolverine
				Fisher
				Badger
			Herbivores - diastema, grinding molars
				Mule Deer	
				Llama
				Cow
				Pocket Gopher
				Beaver
	F) Study of Adaptation - Movement
		1) Adaptations for flight
			a) wing = elongations of the fingers or digits in bats, Pterosaurs
			b) wing = modification of forelimb in birds
			c) hollow bones of birds
		2) Adaptations of limbs for swimming
			a) Flattened skulls for swimming mammals - fusiform shape
			b) limb bones are flattened, elongation of digits and additional 
				bones in the digits
		3) Adaptations for terrestrial movement - walking and running
			a) plantigrade stance - entire foot on ground
				human, armadillo
			b) digitgrade stance - animal is standing on it digits, heel off the ground
				most mammalian predators
			c) unguligrade stance - animal is standing on one foot
				horse
	G) Microscopic examination of bone structure
 			a) bone tissue
				1) Spongy bone and marrow
					a) marrow = site of blood cell production
				2) Compact bone
				3) Haversian systems (osteocytes in lacunae, connected
					to Haversian canal by canaliculi)

II - Muscular systems

	A) Function = movement accomplished by contractile systems
	B) Primitive contractile systems
		1) Cilium and flagellum - 9 + 2 arrangement of
				contractile elements, movement of unicellular 
				organisms
	C) Primitive Muscular Systems
		1) Roundworms - single layer
		2) Segmented worms - double layer
	D) Vertebrate Muscle - different types and arrangements
		1) 3 Types of muscle
			a) Skeletal or striated muscle
				1) contains striations, found in close contact with bones, 
					under voluntary control
			b) Cardiac muscle
				2) heart muscle, contains striations and intercalated 
					discs, discs involved in spreading electric impulses 
					through heart, involuntary control 
			c) Smooth muscle
				3) no striations, lining viscera and vessels, involuntary 
					control
		2) Antagonistic arrangement of most skeletal muscles:Human Muscular System Schematic
			a) Extensors - open the angle between bones and the body
			b) Flexors - closes the angle between bones and the body
		3) Movement and contraction  
			a) Movement is accomplished by contractions of muscle 
				tissue
			b) Contractions - result of movement of filaments across 
				each other
			c) Filaments - thin are actin, thick are myosin, Ca++ entering 
				the muscle cells involved in pulling actin across 
				myosin elements

III Practical Applications

	A) Use of muscle
		1) Strength training - leads to hypertrophy of muscles
			a) muscle mass increases due to an increase in the 
				number of myofibrils and mitochondria
	B) Disuse of muscle
		1) Muscle mass decreases due to lack of use (occurs in elderly 
			or bedridden patients)
		2) Leads to atrophy of muscles - muscle tissue is replaced by fat
	C) Rigor mortis - my friend the squirrel
		1) Death results in an uncontrolled leakage of Ca++ into the 
			cells which stimulates permanent muscle contraction
	D) Genetic Disease - Duchenne's Muscular Dystrophy (information from the MDA)
		1) genetic disease that affects boys, individuals can not produce 
			dystrophin protein (provides support for muscle cells), leads to muscle weakness,  
			degeneration of muscle tissues, loss of muscle cells (atrophy), progressive disease, early signs of lack 
			of coordination, 8-11 years old unable to walk, short life expectancy
	E) Muscle injuries and Remedies
	 	1) Spasm and Cramps - rapid and involuntary contractions 
				of muscles
			a) Spasm - rapid, involuntary contraction of muscle, 
				very painful
			b) Cramp - rapid and sustained contraction of muscle, 
				very painful
		2) Muscle damage
			a) muscle tear due to strenuous exercise - leads to cell 
				damage
		3) RICE - remedy for sports injuries
			a) R - rest, I - ice, C - compression, E - elevation
	F) Aerobic exercise
		1) indirectly affects the muscular system
		2) actually increases size and strength of the heart which 
			increases blood flow to the muscles, able to bring more 
			O2, take away CO2


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Copyright © 2001 Jay Pitocchelli. All rights reserved. The contents of this page are the intellectual property of Dr. Jay Pitocchelli for distribution to students enrolled in General Biology BI 01 at Saint Anselm College. These pages may not be copied, photocopied, reproduced, translated, or published in any electronic or machine-readable form in whole or in part without prior written approval of Jay Pitocchelli. Students enrolled in General Biology BI 01 at Saint Anselm College have permission to print this material for their lecture notes. The images linked to this web page are the sole property of Addison Wesley/ Benjamin Cummings Publishers™.