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Unit 4 Test
Terms in this set (25)
What role do joints play in the human body?
Joints are the place where two bones meet and allow movement and flexibility.
How are joints classified by both structure and function? What terms describe the path of movement at a joint?
Do not move-Ex: joints in dome of skull and between teeth and jawbone
Move little-linked by cartilage-Ex: vertebrae in spine
Move in many directions-found at the hip, shoulders, elbows, knees,wrists, and ankles-filled with synovial fluid (acts as lubricant)-these joints have synovial cavities
What are the different types of synovial joints?
Elbow & knee-movement in one direction only
Head & distal radius-ulna - rotating/twisting movement
Ball and Socket
Hips & shoulders-allows movement in any direction, round end of long bone fits into hollow of another bone
The way in which the parts come together at a joint is called the articulation
What role do cartilage, tendons, and ligaments play at a joint?
Cushions/protects bones where they meet and rub against each other. The cartilage found in joints is hyaline cartilage-the same kind found in a fetal skeleton & it's referred to as articular cartilage where it attaches to articular bone surfaces.
Fibrous tissue that connects muscles to bones
Fibrous straps that fasten bones to other bones
What is range of motion?
Range of motion is the range through which a joint can be moved & can be measured using a goniometer to determine angles.
How do you measure the range of motion of a particular joint movement?
Movement away from body's midline
Movement toward body's midline
Movement at synovial joint in which distal end moves in circle and proximal end remains in one place
Moving bone around its own axis
Unbending movement around limb joint that increases angle between bones of limb at joint
Bending movement around joint in limb that decreases angle between bones of limb at joint
Bending foot down (pointing toe)
Bending foot up
How do bones, muscles and joints work together to enable movement and location for the human body?
Our bones provide support and give our bodies shape, but cannot move on their own. The muscles provide the movement. The joints help attach bones to one another to provide flexibility & allow the muscles to help give the bones a way to move.
How do muscles assist with movement of the body and of substances around the body?
Our muscles are what allow all movement of our bodies (and within our bodies). They help us involuntarily by helping food move down the esophagus and into the stomach (peristalsis) and helping blood move through our bodies (the heart is a muscle). They also help us move our bodies voluntarily from place to place ( the muscles in our limbs). Our bodies each have about 650 muscles & are ~50% muscle by weight!
How do the structure and function of the three types of muscle tissue compare?
They are striated muscle fibers form the wall of the heart & function involuntarily.
They are attached to bone, mostly in the legs, arms, abdomen, chest, neck, and face. They are striated muscle fibers (lined under microscope) & attached to bone by a tendon. They hold the skeleton together and give the shape. They are voluntary (we control them) and contract quickly and powerfully), but they tire easily.
They are smooth (not striated) & are controlled automatically by our nervous system. They are also called "involuntary" muscles. They make up the walls of the stomach and intestine to help break down and move food. They also line the walls of blood vessels. They take longer to contract than skeletal muscles, but also don't tire as easily.
How are muscle fibers and membranes organized to form a whole skeletal muscle?
The epimysium ("upon muscle) is the outermost layer of connective tissue. The perimysium ("around muscle") is made of connective tissue surrounding each individual muscle fiber. Each fascicle is a small cluster of muscle fibers, with endomysium between the individual fibers. Blood vessels run between the fascicles, bring the tissue nutrients & removing waste. Nerves also run throughout, controlling the movement of the muscles. Together, the network of nerves and blood vessels are referred to as the plexus.
How are muscles names?
Several factors are considered when naming a muscle, including
1) Location (EX: tibialis anterior is on the front of the tibia)
2)Shape (EX: deltoid "resembles" (- oid) a "triangle" (delt))
3) Points of attachment (EX: sternoclediomastoid-the muscle attaches to the sternum and the tendons attach to the mastoid process of the skull.)
4) Relative size (EX: gluteal or "rump" region - the gluteus maximus is bigger and the gluteus minimus smaller).
5)Number of muscle "heads" or divisions (EX: Biceps mean "two-headed" and has two divisions)
6) Direction of muscle fibers (EX" the rectus abdominis muscle is located in the front of the abdomen and its fiber are oriented in a "straight" (rect), vertical direction).
7): Association with characters (EX: sartorius means "presence of" (-us) a "tailor" (sartori)! Tailors used to sit cross-legged upon the ground. The sartorius is actually located along the inner aspect of each thigh. Thus, when it contracts, it flexes (bends) the lower leg like an ancient tailor
What do skeletal structure and attachment to bones tell you about function?
Muscles each have an insertion, where they attach to the moveable bone and an stationary bone
What are the requirements for muscle contraction? What is a sarcomere? How does a sarcomere contract and lengthen to cause muscle contraction? How do nerves interact with muscles?
In order for muscles to contract (shorten and thicken), they must receive a message from the CNS to do so. The messages come through efferent neurons (nerves that move away from the CNS). The sliding filament mechanism explains muscle contractions. Muscle fibers contain many myofibrils (―muscle fibers‖) that allow the muscle cells to contract. The myofibrils contain thick and thin filaments attached to the Z disk (Z line). Thick filaments are made of myosin protein and thin ones of actin protein. The two proteins can twist around each other, shortening the sarcomere during contraction. Tropomyosin and troponin are proteins that control how actin and myosin interact—when they contract and twist and when they unravel and relax. Afferent neurons send messages back from muscles to the CNS. If there are problems with nerves, it can lead to issues with muscle function (i.e. Carpal Tunnel Syndrome)
What role do calcium and ATP play in muscle contraction?
1) Calcium ions cause troponin and tropomyosin to shift, exposing myosin binding sites
2) Myosin heads connect with actin binding sites & move the thin filament, contracting the muscle
3) The ADP & P that caused the myosin heads to cock back are left behind during the power stroke
4) Introduction of ATP causes
myosin heads to release the actin
5) ATP is broken down into ADP & P, causing myosin heads to cock back and prepare for another power stroke
How is the condition rigor mortis related to muscle contraction?
After death, the muscle's membranes become more permeable to calcium ions. Those ions promote the cross bridges of actin and myosin, shortening muscle fibers. ATP is needed to release the myosin heads from the actin fibers and allow muscles to relax, but ATP reserves are quickly depleted, causing muscles to remain contracted. It can take 10 minutes to hours to occur, with maximum stiffness 12-24 hours after death. Eventually tissue decays and lysosomal enzymes leak and cause muscles to relax.
How can we assess muscle function?
Heart rate can help assess cardiac muscle function. Strength tests can help assess function of voluntary muscles.
What types of muscle help move blood around the body?
The heart is the primary muscle that helps move blood & is made of cardiac muscle tissue. It is responsible for the circulation of blood & all the materials in it.
What is the relationship between the heart and the lungs? What is the pathway of blood in and out of the heart in pulmonary and systemic circulation?
The right side of the heart collects deoxygenated blood into its atrium & then passes it into the ventricle. The right ventricle then pushes the blood to the lungs, where the CO2 is dropped off and O2 is picked up.
The blood from the lungs comes back to the left side of the heart through the left atrium. It then moves into the left ventricle and the ventricle pushes it out through the aorta (biggest artery) and into the rest of the arteries. The arteries carry oxygenated blood to all of the body's tissues. As they reach the tissues, they turn into tiny arteries called arterioles, which then become capillaries. The capillaries are the place where oxygen, nutrients, and hormones are dropped off and waste products are picked up. The capillaries then turn into venules, which turn into veins, which come together as the vena cava (biggest veins) and carry deoxygenated blood back into the right atrium of the heart.
How does the structure of arteries, veins, and capillaries relate to their function in the body? What unique features of veins help move blood back to the heart?
Three layers of thick, fairly rigid walls to allow them to expand/contract & to handle high pressure (blood has the greatest pressure as it's leaving the heart)—one layer is smooth muscle
Thin walled (one cell layer thick) & microscopic in size to allow exchange of materials, often have pores to allow movement of materials
Thin walled (one cell layer thick) & microscopic in size to allow exchange of materials, often have pores to allow movement of materials
What are varicose veins? Why don't we ever hear about varicose arteries?
Varicose veins are big, twisty veins near the skin's surface that are caused by weakened valves. When the valves don't work (keep blood moving), blood collects in the veins and the pressure builds up, causing them to become weak, large and twisted. They can run in families, but are also caused by age, being overweight and standing for long periods of time
Arteries don't do this because they have higher pressure in them & therefore do not need valves to keep the blood moving.
What are the major arteries and veins in the body and which regions do they serve?
Aorta—blood is pushed out of the aorta by the left ventricle & then the aorta branches into all other arteries in the body
Coronary Artery—this is the artery that runs across the ventral side of the heart, nourishing the cardiac tissue itself
Pulmonary Arteries—carry blood from the right ventricle to the lungs to pick up oxygen
Superior Vena Cava—carries deoxygenated blood from the upper body (arms and head) back to the heart
Inferior Vena Cava-- carries deoxygenated blood from the lower body (abdomen and legs) back to the heart
Pulmonary Veins—carry newly oxygenated blood
from the lungs back to the left atrium
What is cardiac output? How does cardiac output help assess overall heart health? How does an increased or decreased cardiac output impact the body?
Cardiac output is the volume of blood the heart pumps per minute (mL/min) out of the left side. It's calculated by multiplying heart rate (beats/min) by stroke volume (mL/beat). Stroke volume is how much blood is pushed out by the left ventricle with each beat. An average person has a resting heart rate of 70 beats/min and resting stroke volume of 70 ml/beat, leading to a typical cardiac output of 4,900 mL/min. The total volume of blood in an average person is 5,000 mL (5 L), so the whole volume of blood is pumped through the heart about once each minute. During vigorous exercise, it can increase 4-7 fold.
Normal cardiac output is needed to move oxygen and nutrients to all the body's tissues. If a person's cardiac output is lower than normal, the tissues can suffer or blood pressure can become unhealthy. An increased cardiac output from exercise can help strengthen the heart.
What is blood pressure?
Blood pressure is a measure of how fast the molecules in blood are hitting the walls of the arteries. It increases with increased blood volume & with increased heart rate. It is an important indicator of cardiac health and should be under 120/80 at rest.
How can the measurement of blood pressure in the legs be used to assess circulation? What is peripheral artery disease?
The blood pressure in the legs can be taken to measure how well blood is circulating to those limbs. To take the pressure, a person listens to the pulse in that region. Arteriosclerosis ("abnormal condition of hard arteries") & atherosclerosis ("hard arteries due to fat deposits") can both impede blood flow by making the arteries more narrow (that's atherosclerosis) and less flexible (that's arteriosclerosis). That can lead to peripheral vascular disease (PAD), in which blood vessels supplying the extremities do not work as well as they should. The most extreme form of peripheral vascular disease is peripheral artery disease, in which a there is partial or total blockage of an artery, usually one leading to an arm or leg. It causes pain and eventually can even lead to loss of partial or total limbs.
Why can smoking lead to peripheral artery disease?
Smoking raises the risk of atherosclerosis and therefore the risk of PAD. It's thought to do so by damaging the endothelium (innermost layer of the artery), which allows plaque to build up on the artery walls.
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