Muscles Flashcards
What do muscles do?
- Only thing is contract (get shorter)
- Function is movement
- Produce heat to maintain body temperature
Cardiac Muscle Tissue
- Deeply Striated - indicates strength
- Can be deepened/strengthened by exercise
- Strongest muscle!!
- Never fatigues
Why? - after a contraction, the cardiac muscle cell will completely rest before the next contraction - No nucleus in red blood cells
- Branched structure
- Involuntary control
- Found only in heart
- One nucleus per cell
- Individual cells are fused together, to function as one big unit, allowing electrical impulses to travel through all of the cells without additional nerves
- The initial impulse that causes contraction does NOT begin in the brain !!
- Nodal tissue in the heart produces the electrical impulse needed for contraction
Skeletal Muscle Tissue
- Striated - indicates strength
- Can be deepened/strengthened by exercise
- Cylindrical
- Multi nucleated !
- Attached to bones
- Voluntary control – you think about it to move body parts
- Quick to fatigue / Slow to recover
Smooth Muscle Tissue
- NO Striations – Weaker than cardiac and skeletal but NOT Weak
- Found lining the organs (hollow internal organs)
1. Digestive system
2. Reproductive system
3. Circulatory system – walls of the veins and arteries - Shape: spindle shape – thinner at ends than at the center
- Move materials through hollow internal organs
- Form sheets
- One nucleus per cell
- Involuntary – you do not control blood flowing through veins or food going through digestive system etc
- Contracts slowly
- Slow to fatigue / Quick to recover
What do all muscles contain?
- Muscles Tissues
- Connective Tissue
- Nervous Tissue
- Blood Vessels (brings in oxygen, nutrients / removes waste products)
Functions of Skeletal Muscle
- Supports the body – allows you to maintain your posture
- Some skeletal muscle is always contracting, allowing people to stand up straight without thinking about it
- Movement of bones
- Maintains body temperature – produces heat
- Protects internal organs
- Stabilizes joints – synovial joints!!
- Moves blood in veins (heart moves blood in arteries)
- Veins usually found deep inside the skeletal muscle tissue
- When muscle contracts, it puts pressure on outside of the brain which forces the blood back to the heart
- Moves blood in lymphatic vessels
What is the structure of skeletal muscle from largest to smallest?
Muscle, Muscle Bundle, Muscle Fiber, Myofibrils
Muscle
Covered by connective tissue (called fascia) which gets thicker at the ends to form tendons
Muscle Bundle
Bundles of fibers enclosed in connective tissue
Muscle Fiber
Groups of myofibrils
Myofibrils !!!!!!
- Functional unit of a muscle – where contraction starts then it moves up the list
- Can only contract !!
- Proteins → actin and myosin
- Actin and myosin proteins slide past one another causing the myofibril to shorten/contract
- Needs ATP to slide past one another
- Electrical impulse from the brain initiates this process
- Removing the electrical impulse allows the muscle to relax
Muscle Contraction
- Contraction of numerous myofibrils
- Requires electrical stimulation from nervous tissue
- Requires calcium – from bones/bloodstream
- Requires ATP to force actin to slide past myosin
Myoglobin
Stores oxygen in muscle tissue (similar to hemoglobin)
Glycogen
Provides glucose for ATP production
Creatine Phosphate
aids in regeneration of ATP (fast recovery)
Fermentation
- Production of ATP without the use of oxygen
- Leads to a buildup of lactic acid in the tissues
Atrophy
- Shrinkage of muscles do to non-use
- Muscle tissue is replaced by connective tissue and adipose tissue
- If atrophy continues it can contort body parts and pull on tendons
Hypertrophy
- Enlargement of muscles due to an increased number of myofibrils and nervous tissue
- Has to be 75% of maximum strength used
- Has to be on a continuous basis
Good effects steroids in males
- They work
- They promote healing
- They increase mass and weight
Bad side effects in males
- Ache
- Body hair increase
- Potential for anxiety increase
- Shrinkage of testicles
Good effects in females
- They work
- Mass and weight increase
Bad effects in females
- Decrease in breast tissue
- Stops period
- Develop an adam’s apple
- Enlargement of clitoris
- Irreversible
Slow twitch muscle fibers
- Provides endurance
- Slow to fatigue
- Dark in color (myoglobin)
- Greater blood supply
- Aerobic
Fast twitch muscle fibers
- Explosive strength
- Quick to fatigue
- Light in color
- Less blood supply
- Anaerobic
- Produces a byproduct of lactic acid
Origin
Where the muscle attaches to a non moving bone
Insertion
Where the muscle attaches to a moving bone
Prime Mover
A muscle that generates the most force during contractions
Synergists
A small muscle group that stabilizes joints during movement and/or provides extra force
Antagonists
Opposite of what the synergists does
