Examkrackers Biology: Lecture 8

Front 1

What are the three types of muscle and their four possible functions?

Back 1

1. Skeletal 2. Smooth 3. Cardiac

1. Body mvmt 2. Stabilization of body position 3. Mvmt of substances through body 4. Generating heat to maintain body temp

Front 2

Difference between a tendon and a ligament

In reference to muscle, what is an agonist, antagonist, and synergistic muscle?

Back 2

A tendon connects muscle to bone and a ligament connects bone to bone

The agonist, muscle responsible for mvmt, contracts, while the antagonist, stretches
The synergistic muscle assists the agonist by stabilizing the origin bone or by positioning the insertion bone during the mvmt

Front 3

Describe how physics (leverage, F) can be applied to a muscle

Back 3

The elbow can function s a fulcrum, the ulna/radius as a lever, the weight in the hand as the resistance and the muscle in the upper arm as the force applied

-A greater force than mg is required to lift a mass m
-If the muscle has a shorter lever arm, it is closer to the body, and thus creates less bulk

Front 4

Explain what happens during a muscle contraction:
-A band, H zone, I band, Actin, Myosin

Back 4

The H zone and I band get smaller. The A band does not change size.
A sarcomere is the smallest functional unit of skeletal muscle and is made up of a thin filament (actin) and a thick filament (myosin). Attached to actin are the proteins troponin and tropomyosin. Tropomyosin covers the active site on actin so that the myosin head cannot bind, but in the presence of Ca2+, troponin pulls tropomyosin back

Front 5

Describe the function of a T-tubule and the sarcoplasmic reticulum in contraction

Back 5

T-tubule: when an AP occurs, it flows through the T-tubule in order to allow for a uniform contraction by allowing the AP to spread through the muscle more rapidly. The AP is then transferred to the SR, which suddenly becomes permeable to Ca2+ ions - releasing them so that they can bind to troponin. At the end of a 5-stage cycle, Ca2+ is actively pumped into the SR

Front 6

1. Myoglobin
2. Can muscle cells replicate?

Back 6

1.Myoglobin looks like one subunit of Hb. It is only capable of storing one O2 molecule. It stores O2 inside muscle cells.
2. Muscle cells are so specialized that they have lost their ability to undergo mitosis. It is rare for them to split into 2 cells

Front 7

Describe the structure of cardiac muscle cells

Back 7

They are striated like skeletal muscle, which means they have sarcomeres. They only have one nucleus per cell. They are separated by intercalated disks, which contain gap junctions and allows AP's to spread from one cell to the next. Cardiac muscle is involuntary unlike voluntary skeletal muscle

Front 8

Describe the structure of smooth muscle

Back 8

Smooth muscle has one nucleus like cardiac muscle. It also has thick and thin filaments, but they are not organized into sarcomeres, so the cells aren't striated.
Upon contraction, the thin filaments pull the dense bodies together and the cell shrinks length-wise

Front 9

What are the functions of bone?

Back 9

Bone is not just for support, mvmt, and protection. It also stores Ca2+ and phosphate, helping to maintain a balance of these ions in the blood. Bone stores energy in the form of fat. Bone is the site of blood cell formation

Front 10

1. Osteoblasts?
2. Osteocytes?
3. Osteoclasts?

Back 10

1. secrete collagen and organic compounds to help form bone
2. exchange nutrients and waste materials with the blood
3. resorb bone matrix, releasing materials back into the blood

Front 11

1. Most of the Ca2+ in the body is stored in the bone matrix as?

Back 11

1. Hydroxyapatite

Front 12

What are 7 functions of the skin?

Back 12

1. Protection
2. Excretion
3. Vitamin D
4. Immunity
5. Thermoregulation
6. Environmental sensory input
7. Blood reservoir