Biology Ch. 8

Front 1

3 types of of muscle tissue

Back 1

1. skeletal muscle
2. cardiac muscle
3. smooth muscle

Front 2

4 possible functions of muscle contraction

Back 2

1. body movement
2. stabilization of body position
3. movement of substances through the body
4. generating heat to maintain body temp

Front 3

Skeletal muscle

Back 3

-voluntary muscle tissue
-connects one bone to another
-multinucleate

Front 4

Forces due to muscles

Back 4

-muscle uses leverage by applying a force to a bone at its insertion point and rotating the bone in some fashion about the joint
-most lever systems of the body act to increase the required force of a muscle contraction, greater force than mg is required to lift mass m.
-done to reduce bulk of the body and increase range of movement.

Front 5

Tendon

Back 5

tendons attach muscle to bone

Front 6

Ligaments

Back 6

-attach bone to bone

Front 7

Agonist muscles

Back 7

the muscle responsible for the movement; contraction causes an agonist muscle to stretch

Front 8

Antagonist muscles

Back 8

-when contracts, the bone moves in the opposite direction, stretching the agonist.

Front 9

Synergistic muscles

Back 9

-Muscles that assist the agonist muscle by stabilizing the origin bone or by positioning the insertion bone during the movement.

Front 10

Sarcomere

Back 10

-the smallest functional unit of skeletal muscle.
-composed of many strands of two protein filaments, thick and thin filaments, laid side by side to form a cylindrical segment.

Front 11

Sarcoplasmic reticulum

Back 11

-Specialized endoplasmic reticulum that is filled with calcium ions.
-surround the myofibril made up of sarcomeres.

Front 12

Sarcolemma

Back 12

-a modified membrane that wraps several myofibrils together to form a muscle cell or muscle fiber.

Front 13

Thick filament

Back 13

part of the sarcomere made of myosin.

Front 14

Thin filament

Back 14

part of sarcomere composed mainly of polymer of globular protein actin.

Front 15

Actin

Back 15

-globular protein that makes up the thin filament in a sarcomere

Front 16

5 stage actin-myosin cycle

Back 16

1. tropomyosin covers an active site on the actin preventing the myosin head from binding.
-myosin head remains cocked in high-energy position with a phosphate and ADP group attached.
2. in the presence of Ca, troponin pulls tropomyosin back, exposing the active site, allowing the myosin head to bind to the actin.
3. myosin head expels a phosphate and ADP and bends into low energy position, dragging the actin along with it. Called a powerstroke- causes a shortening of the sarcomere and the muscle contraction.
4. ATP attaches to the myosin head. This releases myosin head from active site, which is covered immediately by tropomyosin.
5. ATP splits to inorganic phosphate and ADP causing the myosin head to cock into the high-energy position.

Cycle repeats many times to form a contraction.

Front 17

Motor unit

Back 17

-From 2 to 2000 muscle fibers are innervated by a single neuron
-motor unit is the nerve and muscle fibers that it innervates.
-force of contracting muscle depends upon the number and size of active motor units, and the frequency of action potentials in each neuron of the motor unit.

Front 18

Myoglobin

Back 18

-an oxygen storing protein similar to hemoglobin, but having only one protein subunit.
-high concentration in slow twitch muscle fibers, low concentration in fast twitch muscle fibers.

Front 19

Cardiac muscle

Back 19

-muscle cells contain only one nucleus, separated from neighbor by intercalated disc.
-striated, composed of sarcomeres
-contains gap junction which allow an action potential to spread form one cardiac cell to another via electrical synapses.
-not connected to bone.
-contraction is involuntary.

Front 20

Intercalated disc

Back 20

-separates cardiac muscle cell from neighbor.
-contain gap junctions which allow an action potential to spread from one muscle cell to the next via electrical synapses.

Front 21

Striated muscle

Back 21

-means the muscle is composed of sarcomeres

Front 22

Action potential in a cardiac muscle cell

Back 22

-exhibits a plateau after depolarization.
-plateau is created by slow voltage gated Ca channels which allow calcium to enter and hold the inside of the membrane at a positive potential difference
-lengthens the time of contraction.

Front 23

Smooth muscle

Back 23

-mainly involuntary, innervated by the autonomic nervous system.
-cells contain only one nucleus
-also contain thick and thin filaments, but not organized into sarcomeres.
-contain intermediate filaments, which are attached to dense bodies
-when contract, shrink length-wise

Front 24

intermediate filaments

Back 24

filaments that attach to dense bodies. when thick and thin filaments contract, they cause the intermediate filaments to pull the dense bodies together.

Front 25

Single-unit smooth muscle

Back 25

-cells are connected by gap junctions spreading action potential from a single neuron through a large group of cells, and allowing cells to contract as a single unit.

Front 26

Multi-unit smooth muscle

Back 26

-attached directly ot neuron.
-can contract independently of other muscle fibers in the same location.

Front 27

Bone

Back 27

-a living tissue, functions to support soft tissue, protect internal organs, assist in movement of the body, mineral storage, blood cell production, energy storage.

Front 28

4 types of cells in bone tissue

Back 28

1. osteoprogeniter
2. osteoblasts
3. osteocytes
4. osteoclasts

Front 29

osteoblasts

Back 29

-build bone
-secrete collagen and organic compounds upon which bone is formed
-incapable of mitosis
-release matrix materials around themselves, become enveloped by the matrix and differentiate into osteocytes

Front 30

osteocytes

Back 30

-incapable of mitosis
-exchange nutrients and waste material with the blood
-connected by canaliculi

Front 31

osteoclasts

Back 31

-breakdown bone
-reabsorb bone matrix, release minerals back into the blood
-believed to develop from WBC monocytes

Front 32

Spongy bone

Back 32

-contains red bone marrow, site of rbc development.

Front 33

red bone marrow

Back 33

-site of rbc development in bones

Front 34

Compact bone

Back 34

-dense bone, holds yellow bone marrow

Front 35

Yellow bone marrow

Back 35

-contains adipose cells for fat storage

Front 36

Heversian (central) canals

Back 36

-tunnels burrowed by osteoclasts in compact bone.
-the osteoclasts are followed by osteoblasts, which lay down a new matrix onto the tunnel walls forming concentric rings called lamellae
-contain blood and lymph vessels

Front 37

Neuromuscular synapse

Back 37

-Point where a nueron attaches to a muscle cell
-Action potential of the neuron releases acetylcholine into the synaptic cleft
-The acetylcholine activates ion channels in the sarcolemma of the muscle cell creating an action potential

Front 38

T-tubule

Back 38

-an action potential from the neuromuscular synapse moves deep into the muscle cell via small tunnels in the membrane called t-tubules.
-the action potential is transferred to the sarcoplasmic reticulum which becomes permeable to Ca ions, beginning the 5 stage contraction cycle

Front 39

How the 5 cycle muscle contraction is activated.

Back 39

-Action potential of the neuron releases acetylcholine into the synaptic cleft
-The acetylcholine activates ion channels in the sarcolemma of the muscle cell creating an action potential
-an action potential from the neuromuscular synapse moves deep into the muscle cell via small tunnels in the membrane called t-tubules.
-the action potential is transferred to the sarcoplasmic reticulum which becomes permeable to Ca ions, beginning the 5 stage contraction cycle

Front 40

Lamellae

Back 40

-Concentric rings which are formed when osteoblasts law down new matrix in the Haversian (central) canals of bones.

Front 41

Canaliculi

Back 41

-Tunnels which connect osteocytes trapped between lamellae in bone.
-Means by which the osteocytes exchange nutrients.

Front 42

Volkmann's canals

Back 42

-Haversian canals are connected by these crossing canals in bone

Front 43

Osteon (Haversian system)

Back 43

-The entire system of lamellae and Haversian canal in bone.

Front 44

Forms of calcium in the blood

Back 44

1. bound by proteins
2. bound by phosphates (HPO4^2-) and other anions
3. Free calcium (Ca+) but not much of calcium is free.
-to much free calcium results in membranes becoming hypo-excitable resulting in lethargy, fatigue, memory loss.
-to little results in cramps, convulsions.

Front 45

Hydroxyapatite

Back 45

-Most Ca2+ in the body is stored in the bone matrix as hydroxyapatite
-[Ca10(PO4)6(OH)2].
-crystals lie alongside collagen fibers, and give the bone greater compressive strength than the best reinforced concrete.

Front 46

How does bone function in the storage of calcium?

Back 46

-stores hydroxyapatite crystals (most Ca2+ is stored this way)
-Some of the Ca exists in bone as slightly soluble calcium salts such as CaHPO4--> buffer the plasma Ca levels.
-bone acts as a storage sight for both calcium and phosphate.

Front 47

Cartilage

Back 47

-flexible, resiliant connective tissue
-composed primarily of collagen, has great tensile strength
-contains no blood vessels or nerves except in its outer membrane.

Front 48

The seven functions of skin

Back 48

1. Thermoregulation-blood conducts heat form the core of the body to skin
2. Protection-skin a physical barrier to abrasion, bacteria, dehydration, chemicals, UV light.
3. Environmental sensory input-temp, pressure, pain, touch
4. Excretion-loss of water and salts
5. Immunity-specialized cells of the epidermis contain components of the immune system
6. Blood reservoir-vessels in the dermis hold 10% of blood
7. Vitamin D synthesis

Front 49

2 principle parts of the skin

Back 49

1. Epidermis
2. Dermis

Front 50

Epidermis

Back 50

-Avascular epithilial tissue that is part of the skin
-5 strata or layers of epidermis
-when cells reach the outermost layer of the skin they slough off the body

Front 51

Callus

Back 51

-exposure to friction or pressure stimulates the epidermis to thicken forming a callus.

Front 52

Dermis

Back 52

-connective tissue derived from mesodermal cells
-embedded by blood vessels, nerves, glands, and hair follicles.