Anatomy Test 3
Terms in this set (91)
What is a joint?
Site where two or more bones meet
What holds bones together at joints?
Ligaments (connective tissue, tough, connects from one bone to another, not very long)
Connects muscle to bone
What are the 5 golden rules of skeletal muscle activity?
1. With a few exceptions, all skeletal muscles cross at least 1 joint
2. The bulk of a skeletal muscle lies proximal to the joint it crosses
3. All skeletal muscles have at least 2 attachments - origin and insertion
4. Skeletal muscles can only pull, never push
5. During contraction, a skeletal muscle insertion moves towards the origin
Less movable point of attachment
More movable point of attachment
What does "antagonist" mean?
Muscles that oppose or reverse a movement
What are the three types of muscle tissue?
Skeletal, smooth, cardiac
Decreases the angle of a joint
Moving away from the midline
Increases the angle of a joint
Compare locations of different muscle types
Skeletal: attached to the bones, or for some facial muscles, to the skin
Cardiac: walls of the heart
Smooth: mostly in walls of visceral organs (except the heart)
Moving toward the midline
Movement of a bone around its longitudinal axis
Compare cell shape and appearance of different muscle types
Skeletal: single, very long, cylindrical, multinucleate cells with very obvious striations
Cardiac: branching chains of cells; uninucleate, striations; intercalated discs
Smooth: single, fusiform, uninucleate; no striations
What are the functions of muscles?
- Produce movement
- Maintain posture
- Stabilize joints
- Generate heat
List the microscopic anatomy of skeletal muscle from largest to smallest
2. Fascicle (bundle of cells)
3. Muscle fiber (cell)
5. Myosin (myofilament)
6. Actin (myofilament)
Steps for muscle contraction
1. The end of a neuron receives action potential (message)
2. Ach is released from presynaptic membrane (neuron)
3. Ach bonds with receptors on sarcolemma
4. Action potential (message) moves through muscle cell; across the surface as well as through T tubules
5. Sarcoplasmic reticulum releases Calcium ions
6. Calcium attaches to actin and exposes myosin head binding sites
7. Myosin bonds with binding sites on actin; cross bridges form
8. Myosin heads pivot towards center of sarcomere
9. ATP allows for myosin heads to detach and re-cock for the next power stroke
What is the role of calcium in muscle contraction?
It makes it possible for myosin to bind to actin by exposing binding sites
How do you prevent muscle loss?
1. Exercise (endurance and resistance)
2. Energy (creatine phosphate, aerobic respiration, anaerobic respiration)
How do you name skeletal muscles?
1. Direction of muscle fibers (ex. rectus - fibers run parallel to midline)
2. Relative size of muscle (ex. maximus - largest, minimus - smallest, longus - long)
3. Location of the muscle (ex. temporalis - overlies temporalis bone of skull)
4. Number of origins (ex. biceps - two origins, triceps - three origins, quadriceps - four origins)
5. Location of the muscle's origin and insertion (ex. sternocleidomastoid - origin on sternum and clavicle and inserts on mastoid process of temporal bone)
6. Shape of muscle (ex. deltoid - triangular)
7. Action of muscle (ex. adductor muscles of the thigh bring about its adduction, extensor muscles of the wrist extend all the wrist)
What are the functions of muscle fibers?
1. Irritability/responsiveness - ability to receive and respond to a stimulus
2. Contractility - ability to forcibly shorten when adequately stimulated
3. Extensibility - ability of muscle fibers to stretch
4. Elasticity - ability to recoil and resume their resting length after being stretched
Long threadlike extension of the neuron, branches into axon terminals when reaches the muscle
Consists of one neuron and all the skeletal muscle fibers it stimulates
Separates the nerve endings and the muscle fiber membranes, the synaptic cleft is filled with interstitial fluid
Contain synaptic vesicles filled with a chemical referred to as a neurotransmitter (ACh is a specific neurotransmitter that stimulates skeletal muscle fibers)
Where does the energy required for muscle contraction come from?
As a muscle contracts, the bonds of ATP molecules are hydrolyzed to release the needed energy
The Sliding Filament Theory
Explains the mechanism of muscle contraction based on muscle proteins that slide past each other to generate movement
How is ATP regenerated?
1. Direct phosphorylation of ADP by creatine phosphate (CP)
As ATP is depleted, interactions between CP and ADP result in transfers of a high-energy phosphate group from CP to ADP, thus regenerating more ATP in a fraction of a second.
2. Aerobic pathway
Occurs in the mitochondria and involves a series of metabolic pathways that involve oxygen, glucose is broken down to carbon dioxide and water, and some of the energy released as the bonds are broken is captured in the bonds of ATP molecules
3. Anaerobic glycolysis and lactic acid formation
Glycolysis: glucose is broken down to pyruvic acid, and small amounts of energy are captured in ATP bonds. When muscle activity is intense, or oxygen and glucose delivery is temporarily inadequate to meet the needs of working muscles, the aerobic pathways cannot keep up with demands for ATP; under these conditions, the pyruvic acid generated during glycolysis is converted to lactic acid.
Receive blood from body
Carry blood away from the heart
What are the four chambers of the heart?
Right atrium, right ventricle, left atrium, left ventricle
Pump blood out of the heart
Small vessels that gather blood from the capillaries into the veins
Carry blood from the heart to body and back
Small vessels that receive blood from the arteries
Connective tissue consisting of several types of cells suspended in a liquid matrix (plasma)
- Microscopic vessels through which exchanges take place oxygen and other nutrients from the bloodstream
- Branch through the tissues and connect the smallest arteries (arterioles) to the smallest veins (venules)
- Very thin so substances are exchanged easily
- Form interweaving capillary beds
Drain the tissues and return the blood to the heart
What are the differences between arteries and veins?
- Arteries are deeper and veins are superficial
- Arteries have a smaller diameter and veins have a larger diameter
- Arteries have thicker walls and veins have thinner walls
- Arteries carry blood away from heart and veins carry blood toward the heart
- Arteries don't have valves and veins have valves
- Arteries have a pulse and veins don't have a pulse
- Arteries have a higher velocity and veins have a lower velocity
- Arteries generally carry oxygenated blood and veins generally carry deoxygenated blood
Sequence of blood flow
1. Deoxygenated blood enters right atrium through 2 veins: superior and inferior vena cava
2. Blood moves from right atrium to right ventricle through atrioventricular valve
3. Right ventricle contracts and pumps blood into pulmonary artery through semilunar
4. Pulmonary artery carries blood to right or left lung where gas exchange occurs
5. Oxygenated blood returns to heart via the pulmonary veins: enters left atrium
6. Blood moves to left ventricle through another AV valve
7. Left ventricle contacts and pumps blood into aorta through aortic semilunar valve
8. Aorta branches and oxygenated blood is sent to body
Gets oxygen into blood
Steps for pulmonary circulation
Heart (deoxygenated) → lungs → heart (oxygenated)
Goes from right ventricle, travels out pulmonary artery, goes to lungs, goes through the pulmonary veins, goes to left atrium
Steps for systemic circulation
Heart (oxygenated) → body → heart (deoxygenated)
Goes from left ventricle, out the aorta, to body, through the superior and inferior vena cava, to right atrium
What do heart valves do?
Allow blood to flow in one direction to prevent backflow
Delivers oxygenated blood to all body tissues
What are the types of heart valves?
1. Atrioventricular (AV) Valves - between atria and ventricles, prevent back flow into atria when ventricles contract, AV valves cusp upward (left AV valve: bicuspid/mitral valve, right AV valve: tricuspid valve)
2. Semilunar Valves - pulmonary and aortic semilunar valves, have three cusps that get filled with blood when ventricles relax to prevent back flow to the heart
Beat of the heart as felt through the walls of the arteries
Number of beats per minute (lower heart rate is healthier)
The pressure the blood exerts against the inner walls of blood vessels, and it is the force that keeps blood circulating continuously even between heartbeats
Rhythmic contraction and relaxation of heart muscle
Contraction of the heart (top number on blood pressure reading)
Relaxation of the heart (bottom number on blood pressure reading)
The volume of blood pumped from a ventricle of the heart in one beat (stroke volume is highest when you are working your heart, such as when you are exercising)
The amount of blood that leaves the heart in one minute, stroke volume x heart rate
Steps for cardiac cycle
1. Atrial and ventricular diastole (AV valves open, semilunar valves closed)
2. Atrial systole; ventricular diastole (AV valves open, semilunar valves closed)
3. Ventricular systole; atrial diastole (AV valves closed, semilunar valves open)
A closed transport system made up of blood vessels (where blood circulates)
Steps for vascular system
1. As the heart beats, blood is propelled into the large arteries leaving the heart
2. The large arteries branch and blood moves into smaller and smaller arteries and then into arterioles
3. Arterioles feed the capillary beds in the tissues
4. Capillary beds are drained by venules
5. Venules empty into veins that merge together and empty into the great veins (vena cave) entering the heart
Lub (AV valves close) and dup (semilunar valves close)
If bp is too high, what would the kidneys do?
- The kidneys allow more water to leave the body in the urine
- Because the source of this water is in the bloodstream, blood volume decreases, which decreases blood pressure
If bp is too low, what would the kidneys do?
- The kidneys retain body water, maintaining blood volume and blood pressure
- In order for this to happen, fluids must be ingested or administered intravenously
Widens the blood vessels, which decreases blood pressure
Narrows the blood vessels, which increases blood pressure
What is the difference between the exchange of fluids in the arteriole end of a capillary and a venule end of a capillary
At the arterial end of a capillary, blood pressure is more than osmotic pressure, and fluid flows out of the capillary and into the interstitial fluid. At the venule end of a capillary, blood pressure is less than osmotic pressure, and fluid flows from the interstitial fluid into the capillary.
Where in the blood's circulation is blood pressure the highest in the body? The lowest?
The pressure is highest in the large arteries closest to the heart and continues to drop throughout the systemic pathway, reaching zero in the right atrium.
What effect does bleeding have on blood pressure?
Blood pressure will drop as blood flows through the pulmonary pathway
What effect does the sympathetic nervous system have on blood pressure?
The major action of the sympathetic nerves on the vascular system is the cause vasoconstriction, or narrowing of the blood vessels, which increases blood pressure
What effect does standing up have on blood pressure?
Gravity causes blood to pool very briefly in the vessels of the legs and feet and blood pressure drops
What effect does nicotine have on blood pressure?
Increases blood pressure by causing vasoconstriction
What effect does alcohol have on blood pressure?
Causes vasodilation and decreases blood pressure
What effect does vasodilation have on blood pressure?
Widens the blood vessels, which decreases blood pressure
What is angiotensin and when is it released?
- A vasoconstrictor
- When blood pressure is low, certain kidney cells releases renin, an enzyme, into the blood. Renin triggers a series of chemical reactions that result in the formation of angiotensin, a potent vasoconstrictor chemical
What does sodium do for blood volume and how does it relate to blood pressure?
- Angiotensin stimulates aldosterone, which enhances sodium ion reabsorption by the kidneys
- As these sodium ions move into the blood, water follows
- This water enters the bloodstream and therefore increases blood volume and blood pressure
Intrinsic conduction system/nodal system
- Sets the basic rhythm for the heart
- Allows for the heart to beat as a coordinated unit
- Contains sinoatrial (SA) node, atrioventricular (AV) node, atrioventricular (AV) bundle, left and right bundle branches, and Purkinje fibers
- Pacemaker of the heart
- Maintains heartbeat rhythm by setting the rate at which all cardiac cells contract
- Located in wall of right atrium near where superior vena cava enters
Impulses from SA node pass to AV node which is located in the lower wall of right atrium
Control of Heart Beat
1. SA node sends an electrical impulse throughout atria to cause them to contract simultaneously
2. Signal reaches AV node 0.1 sec later
3. Signal passes through bundle branches and Purkinje fibers to reach tip of heart and both ventricles contract simultaneously
Plasma membrane of a muscle cell
A muscle cell
A bundle of muscle cells
A long, filamentous organelle found within muscle cells that has a banded appearance
Structure that contains actin and myosin
Running; Increases blood flow, brings calcium and oxygen to the muscle, increases mitochondria. Better digestion and metabolism. Makes skeleton stronger.
Lifting weights; You are forcing muscles to contract in order for response. We get bigger muscles in response by increasing cell size (hypertrophy). Atrophy is when cells shrink.
Why is it important to exercise?
Muscle cells shrink when you do not use your muscle
Relationship between a muscle fiber, a myofibril and a myofilament
Muscle fibers are muscle cells made up of myofibrils. Myofilaments are a threadlike proteins found in myofibrils. They help lead to force production and motion
Membrane surrounding the heart. Made of three layers. Outer fibrous layer and an inner serous membrane pair.
What are the three layers of the heart?
Epicardium: outer layer of the heart and visceral layer of serous pericardium
Myocardium: Thick bundles of cardiac muscle. This layer is the layer that actually contracts.
Endocardium: Inner lining of the heart- helps blood flow smoothly
Ball and socket joint
Allows for rotation. Joint with a rounded surface moves within a depression of another joint ie. the femur in the pelvis and shoulder
Allows for flexion and extension (ankle, elbow, knee)
A freely movable joint that allows movement around a single axis. (Neck allows you to rotate your head)
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