Biol 1110- Skeletal + Muscular System

What are the components of the skeletal system?

Bone, cartilage, tendons, ligaments

Functions of the skeletal system

Support, protection, prod. of blood cells, storage of minerals + fats, permits movement of bones @ joints

What is the longest and shortest bone?

Longest - femur

Shortest - ossicles in middle ear (stapes smallest)

What is the axial and appendicular skeleton?

Axial - consists of bones along midline of body (cranium, vertebral column, ribcage, sternum, sacrum, coccyx)

Appendicular - consists of bones of limbs (arms + legs) plus bones they hang off of (shoulders, arms, hands, fingers, hips, legs, feet, toes)

What are the three types of joints?

Ball and socket: provides 360 degrees of movement (shoulder + hip)

Hinge joint: 90 degree movement in one direction )jaw, knee, elbow, hands, feet, wrist, ankle)

Pivot joint: Allows rotation around single axis )elbow, neck)

Skeletal system and homeostasis

Cardio syst: Prod of white + red blood cells, platelets in red bone marrow of spongy bone

Muscular syst: Bones provide anchoring point for muscles, allowing movement

Lymphatic syst: White blood cells made in bone marrow help with immune response

Nervous syst: Cranium protects brain, vertebral column protects spine

Respiratory syst: Rib cage allows for attachment of muscles essential for breathing, protects lungs

Digestive syst: Bones store dietary calcium + phosphates

Where are the longest muscle fibres found?

Sartorius: bends thigh at hip, rotates thigh outward, bends lower leg at knee

What are the largest, strongest and smallest muscles?

Largest: gluteus maximus

Strongest: masseter of jaw

Smallest: found in iris of eye

Functions of the muscular system

Movement of substances through tubes, vessels + organs, blood flow through heart, movement of bones @ joints, respiration by action of diaphragm + intercostals, protection of inner organs, regulation of body temp

Movement of substances

Smooth muscles responsible for peristalsis

Smooth muscle found in digestive, urinary, and reproductive systems and responsible for movement of substances

Regulation of body temp

Caused by involuntary contraction of skeletal muscles (shivering) to generate heat when body temp drops

How do bones move at joints?

skeletal muscles shorten or contract

What is the point of origin?

End attached to bone that is the anchor: stays stationary when muscle contracts

What is the point of insertion?

End of bone that will move when muscle contracts

What is the path of an impulse/ muscle contraction?

Motor neuron —> neuromuscular junction (acetylcholine released) —> depolarization of muscle triggers calcium release—> leaves axon —> trasmitted across gap to muscle fibre, contraction

True or False, acetylcholine is not a crucial neurotransmitter

False, it is and enables impulses to cross a gap to the muscle fibre

What does acetycholine stimulat?

release of calcium ions from sarcoplasmic reticulum (special muscle cells),which cause contraction

What is the contraction of muscle fibers due to?

sliding of actin filaments in a region called sarcomere

Sarcomere

“Sliding” units found within a muscle group, action fueled by ATP—> allowing myosin heads to pull actin filaments towards middle of sarcomere—> causing contraction

Skeletal muscle

Skeletal syst: movement of bones @ joints

Respiratory syst: Diaphragm and intercostal muscles responsible for breathing

Integumentary syst: Involuntary contraction of SM in skin releasing heat when body temp decreases

Cardio syst: contrac. moves blood in veins

Nervous syst: Contract. moves eye muscles

Lymphatic syst: contract, moves lymph in vessles

Smooth muscle

Digestive syst: SM in walls of stomach and intestines accounts for peristalsis

Urinary syst: Muscle contractions move urine out of body

Cardio syst: muscle actions in walls of arteries adjust BP

Nervous syst: SM control size of pupil

Lymphatic syst: SM in walls of lymph vessels

Cardiac muscle

Cardio syst: CM forms walls of heart and pumps blood from heart to the body systems