Biomed module 10 obj. 1-6
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What are the four funciotns of muscle tissue?
- 1. Producing body movements
- 2. stablilizing body posistion
- 3. storing and moving substances within in the body
- 4. Generating heat
Producing body movements
- -Flexion and extension, adduction and abduciton
- -pumping action of the heart by the cardiac muscle
- -peristaltic (milking) movements withnin the digestive tract.
Stablilizing body posistion
Without muscle activity, not just movement would cease; also the constant battle of the body against gravity would be lost.
Storing and moving substances within in the body
- Digestive enzymes are kept in the pancreas by a specialized circular muscle called the sphincter
- When a meale arives and is detected thy athe sphincter, it relaxes and geleases its cargo of digestive juices.
- Lymph fluid is pushed around by muscular action having no pump of its own.
Muscles generate heat
- body heat (waste muscle energy)
- When it is cold, our bodies immediately begins muscle contractions (shivering) to create heat (wast muscle energy) and resotre temperature homeostasis
- also called volentary muscle
- under our volentary control
- moves body at joints
- Long tubes formed from fusion of multiple embrionic cells (syncytium)
- dozens or hundreds of nuclei, along outside of fused muscle cell
- Like skeletal muscle they are striated (tiger srtiped pattern)
- found only in the heart
- not under volentary control
- single cell, branched, connected at intercalated discs
- single nucleus along outside of baranched muscle cell
- not striated
- smooth appearance
- single cells, unbranched, spindle shaped
- not under volentary control
- single nucleus in center of cell
- located in arteries and the gut tube
The ________ of muscle cells is basically the same as the __________ of any other cell.
Like all cells, muscle cells have _____ _________made up of _______ ______ strung togethe like beads on a string to make loing rods.
thing filaments, globular actin
Muscle cell proteins
- Muscle cells use actin (same as microfilament protein in all cells)
- Aslo use myosin (protein that interacts with actin to cause contractions)
- Regulatory proteins control the interaction between actin and myosin
- Structural proteins keep myosin and actin in teh correct orientations
- -especially in striated muscle (skeletal and cardiac)
- -gives striated musle its charcteristic appearance
The key feature of skeletal muscle is its _________(stripes). these are seen because ______ and ______ occur in a regular array called a sarcomere.
striations, actin, myosin
- basic unit of muscle contraction
- a regular arrangement of actin and myosin filaments plus structural proteins to hold things in place
- about 2um long
- when muscle is relaxed, sarcomeres are t their maximum width
- when sarcomeres collapse on the mselves and becom shorter, the entire muscle becomes shorter
- as each of these shortens by a tiny amount, the entire muscle is contracted.
True or False: Skeletal muscle is controlled by the nervous system.
- True : Nerurons (nerve cells) inthe poinal cord send out a cable-like axon which ends in a neuromusclular junction.
- the signal sent at this junction triggers contraction of the entire muscle fiber
- if one sarcomere shortens, they all do
Cardiace muscle has _________. The ________ muscle contracts due to the combined action of millions of sarcomeres working in a __________ fashion.
sarcomeres, heart, coordinated
_______ muscle is controlled by a nerve cell that makes synaptic (_____ to _____) contact with the muscle fiber.
Skeletal, cell, cell
- cardiac muslce electrical signaling system
- sends an electrical spike every 0.8 seconds to cause the heart to contract 72 times a minute (heart rate/pulse)
In responst to _________ or emotional stress, the ________ system sends a signal that increases the _______ _______. Acting through the neurotransmitter and hormone adrnaline (_________), the _________ system and endocrin system ______ the heart rate when needed.
physical, nervous, heart rate, epinephrine, nervous, increase
True or False: The heart rate is controlled for the entire muscle, not for individul muscle fibers as it is for skeletal muscle
The cardiac muscle has ____________ control. That is it continues even if we are unconscious and we cannot alter its rate by _______ ______ __.
involentary, thinking about it
Cardiac muscle is put together in such a way that the entire muscle...
...contracts all the way all at once. This makes the heart work as a pump.
In order to acheive this, the heart muscle cells have a series of gap juncitons that trnasmit the electrical signal for contraciton all the way through the entire muscle simultaneously
Structurally, the cardiac muscle needs to be strong so that it dosen't ____ _____ _____ with the constant, regular ________. In order to do this the heart has intercalated discs.
rip itself apart, contractions
- found in cardiac muscle
- regions with multiple desmosomes holding the muscle cells together
- remember desmosomes are "spot-welds" that give a tissue structural integeity and strength
________ muscle is found linning blood _______, lining airways, lining the _____ tube throughout the digestive system, and a number of other ______.
Smooth, vessels, tube, gut, places
Smooth muscle is not under voluntary control. Blood vessels expand and conctract, __________ open and constrict, our _______ dilate and constrict and our ______ keeps things moving, even while we sleep.
airways, pupils, gut
The nerves that innervate smooth muscle are there to...
...regulate smooth muscle contractions rather then control it.
the nerve cells release chemical that increase or decrease the overall activity level of smooth muscle, but they dont control individul muscle cells as in skeletal muscle.
True or False: the digestive system has its own nervous system that helps coordinate and control contraction of large blocks of smoooth muscle, to keep things moving from mouth to anus without needing the brain to tell it what to do.
True or false: The brain runs the show when it comes to smooth muscle.
The brain is capable of makeing helpful suggestions but is dosen't run the show.
a long strand of sarcomeres (many thousands) arranged end to end.
Several dozen myofibrils are found inside of each __________ ____, or ______ ______. This is the syncytium that resuslts when ________ muscle cells fuse to form a long tube.
muscle cell, muscle fiber, embryonic
What are the levels of organization of the Muscle fiber/Cell?
- One muscle fiber (muscle cell) is the product of many embryonic muscle cells fusing into one long tube (syncytium) with multiple nuclei.
- Each muscle fiber runs the entire length of a muscle
- Each muscle fiber is surrounded by the plasma membrane of the cell (sarcolemma)
- Inside the muscle fiber are sacs and tubules and dozens of myofibrils divided into sacromeres
- -The sarcomere is the funcitonal unit of striated and cardiac muscle
- "grain" of meat on the butcher shop
- represents a strong bundle of sticks
- several dozen muscle fibers bound together by a connective tissue sheath.
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