A&P - Chapter 17 (Part 4) Flashcards
What kind of contractions produce movement at a joint?
Isotonic contractions
What happens in isotonic contractions?
Muscle changes length, but the tension is the same
What are 2 types of isotonic contractions?
- Concentric contraction
2. Eccentric contraction
Concentric contraction
Muscle shortens as it contracts
- insertion end of the muscle moves towards the point of origin
Eccentric contraction
Muscle lengthens while contracting
- produces tension so insertion moves away from point of origin
What type of movement are most types of body movements?
Isotonic contractions
Isometric contractions
Tension within muscle increases but muscle doesnt shorten
- no movement
What is an example of isometric contractions?
Pushing against a wall
Iso
Same
Metric
Length/measure
What is relatively the same regardless of whether muscle is contracted or relaxed in isometric contractions?
Muscle length
What does repeated isometric contractions do?
Muscles stronger
What improves muscle tone and posture?
Regular, properly practiced exercise
What does regular, properly practiced exercise result in? (4)
- More efficient heat and lung functions
- Reduces fatigue
- Helps muscle tissue develop
- Helps maintain a healthy weight
Do muscles or fat have a higher metabolic rate?
Muscles
What is muscles change related to?
The amount of work they do
Atrophy
Prolonged inactivity causes disuse
Hypertrophy
Regular exercise increases muscle size
Strength training
Exercise involving contractions of muscles against heavy resistance
What is an example of strength training? (3)
- Weight lifting
- Squats
- Planking
What happens to the muscle fibres during strength training?
Increases number of myofilaments in each muscle fibre
- doesnt increase the number of muscle fibres
What happens to the total mass of the muscle in strength training?
Increases it
Endurance training
Exercise that increases a muscle’s ability to sustain moderate exercise over long periods of time
What is endurance training sometimes called?
Aerobic training
What does endurance training allow? (2)
- More effective delivery of oxygen and nutrients to a muscle via increased blood flow
- Increases the number of mitochondria and blood vessels in a muscle
What does the cardiac muscle mostly compose?
The bulk of the heart
Intercalated disks
Cells that branch frequently and are joined to each other by unique dark bands
What do intercalated disks enable?
Interconnected nature of cardiac muscle cells allowing heart to contract efficiently as a unit
What kind of control is cardiac muscle?
Involuntary
What do cardiac muscle contain? (2)
- Many nuclei
- centrally located - Loaded with mitochondria
- doesnt get tired (lots of energy)
What is smooth muscle also called? (3)
- Non-striated
- Involuntary
- Visceral muscle
What do smooth muscles line? (3)
- Digestive tract
- Blood vessels
- Ureters
What kind of control do smooth muscles have?
Involuntary
What does muscle functioning depend on? (2)
- Bones and joints
2. Respiratory, circulatory, nervous and skeletal systems
What are examples of diseases that can negatively affect our ability to move? (4)
- MS
- Stroke
- Spinal cord injury
- Arthritis
