Instructions: Type your answers IN BOLD, following the selected Checkpoint questions. Week 1
1.What is the basic difference between anatomy and physiology? (p. 2) ANSWER: Anatomy is the study of body structure and Physiology is the study of body function.
2.Define each of the following terms: atom, molecule, cell, tissue, organ, system, and organism. (p. 6) ANSWER: atoms, the smallest units of matter that participate in chemical reactions
molecules, two or more atoms joined together.
The cell is the basic, living, structural and functional unit of the body.
Tissues are groups of cells and the materials surrounding them that work together to perform a particular function. Organs usually have a recognizable shape, are composed of two or more different types of tissues, and have specific functions.
A system consists of related organs that have a common function. All the systems of the body combine to make up an organism.
3.How are negative and positive feedback systems similar? How are they different? ANSWER: The basic difference between negative and positive feedback systems is that in negative feedback systems, the response reverses a change in a controlled condition, and in positive feedback systems, the response strengthens the change in a controlled condition.
4.Describe the anatomical position and explain why it is used. (p. 15) ANSWER: In the anatomical position, the subject stands erect facing the observer, with the head level and the eyes facing forward. The feet are flat on the floor and directed forward, and the arms are at the sides with the palms facing forward. Scientists and health-care professionals refer to one standard anatomical position and use a special vocabulary for relating body parts to one another so there is no confusion.
5.What are the various planes that may be passed through the body? Explain how each divides the body. ANSWER: Asagittal plane (SAJ-i-tal; sagitt- = arrow) is a vertical plane that divides the body or an organ into right and left sides. More specifically, when such a plane passes through the midline of the body or organ and divides it into equal right and left sides, it is called a midsagittal plane. If the sagittal plane does not pass through the midline but instead divides the body or an organ into unequal right and left sides, it is called a parasagittal plane (para- = near). A frontal plane or coronal plane divides the body or an organ into anterior (front) and posterior (back) portions. A transverse plane divides the body or an organ into superior (upper) and inferior (lower) portions. A transverse plane may also be called a cross-sectional orhorizontal plane. Sagittal, frontal, and transverse planes are all at right angles to one another. An oblique plane, by contrast, passes through the body or an organ at an angle between the transverse plane and a sagittal plane or between the transverse plane and the frontal plane.
6. Compare the meanings of atomic number, mass number, ion, and molecule. (p. 29) ANSWER: The number of protons in the nucleus of an atom is called the atom's atomic number The total number of protons plus neutrons in an atom is its mass number. If an atom either gives up or gains electrons, it becomes an ion when two or more atoms share electrons, the resulting combination of atoms is called a molecule. 7. What functions does water perform in the body? ANSWER:
Water is an excellent solvent
Water participates in chemical reactions.
Water absorbs and releases heat very slowly.
Water requires a large amount of heat to change from a liquid to a gas.
Water serves as a lubricant
8. Why is ATP important?
ANSWER: ATP is the primary source of free energy in all living cells. ATP provides the energy for muscles to contract, nerves to conduct impulses, and all that cells require to build protein, pump in substances they need, permit enzymes to act, and so on. All living organisms require ATP.
9. What are the functions of electrolytes in the body?
ANSWER: Electrolytes control the osmosis of water between fluid compartments, help maintain acid–base balance, carry electrical current, and act as enzyme cofactors.
10. What are the major physiological effects of acidosis and alkalosis? ANSWER: acidosis is a condition in which blood pH is below 7.35, alkalosis is a condition in which blood pH is higher than 7.45; b) acidosis: depression of the CNS through depression of synaptic transmission; alkalosis: overexcitability in both the CNS and peripheral nerves resulting in nervousness, muscle spasms, and even convulsions and death.
11. What is meant by selective permeability?
ANSWER: The property of a membrane or other material that allows some substances to pass through it more easily than others.
12. What is the key difference between passive and active transport? ANSWER: The cell has to use energy for active transport for example endocytosis. Passive transport does not require the cell to use energy, for example difussion.
13. How does diffusion through membrane channels compare to facilitated diffusion? ANSWER: In simple diffusion, substances cross a membrane through the lipid bilayer; in facilitated diffusion, ion channels or carriers are involved.
14. Why is the nucleus so important in the life of a cell? ANSWER: The nucleus controls all actions of the cell, and without the nucleus, the cell would die because it doesn't know how to do anything without the nucleus telling it how to survive and what to do to survive. Chapter 4
15. Define a tissue. What are the four basic types of body tissues? ANSWER: A tissue is a group of similar cells, usually with a common embryonic origin, that function together to carry out specialized activities.
Epithelial tissue, Connective tissue, Muscular tissue, Nervous tissue
16. What are the functions of muscular tissue?
ANSWER: muscular tissue produces motion, maintains posture, and generates heat. It also offers protection
17. Name the three types of muscular tissue.
ANSWER: Skeletal muscle tissue, Cardiac muscle tissue, Smooth muscle tissue
18. What structures are included in the integumentary system? ANSWER: The superficial, thinner portion, which is composed of epithelial tissue, is the epidermis. The deeper, thicker connective tissue portion is the dermis
19. What are the three pigments found in the skin, and how do they contribute to skin color? ANSWER: Melanin, Carotene, and hemoglobin are the three pigments that impart a wide variety of colors to skin. The amount of melanin causes the skin's color to vary from pale yellow to reddish-brown to black. The red color is due to hemoglobin, the oxygen carrying pigment in red blood cells.
20. In what two ways does the skin help regulate body temperature? ANSWER: By protecting our sensitive organs from excessive heat and cold, and by producing sweat, which cools us down when it evaporates.
21. In what ways does the skin serve as a protective barrier? ANSWER: Keratin in the skin protects underlying tissues from microbes, abrasion, heat, and chemicals, and the tightly interlocked keratinocytes resist invasion by microbes. Lipids released by lamellar granules inhibit evaporation of water from the skin surface, thus protecting the body from dehydration. Oily sebum prevents hairs from drying out and contains bactericidal chemicals that kill surface bacteria. The acidic pH of perspiration retards the growth of some microbes. Melanin provides some protection against the damaging effects of UV light.
22. Give several examples of long, short, flat, and irregular bones. ANSWER: Short bones: carpals and tarsals (bones in your fingers and toes) Flat bones: Calvarium (skull bone), sternum, or scapula
Long bones: femur, tibia and fibula (all leg bones) or humerus, radius and ulna (arm bones) Irregular bones: bones that can't fit into the above categories, such as vertebrae (spine), hyoid, maxilla and mandible (jaw), and the bones of your sinuses: ethmoid, zygomatic, and sphenoid
23. What are the four types of cells in bone tissue?
ANSWER: osteogenic cells, osteoblasts, osteocytes, and osteoclasts.
24. What is bone remodeling? Why is it important?
ANSWER: Bone remodeling is the ongoing replacement of old bone tissue by new bone tissue. It involves bone resorption, the removal of minerals and collagen fibers from bone by osteoclasts, and bone deposition, the addition of minerals and collagen fibers to bone by osteoblasts. Thus, bone resorption results in the destruction of bone extracellular matrix, while bone deposition results in the formation of bone extracellular matrix. Remodeling takes place at different rates in different regions of the body. Even after bones have reached their adult shapes and sizes, old bone is continually destroyed and new bone is formed in its place. Remodeling also removes injured bone, replacing it with new bone tissue. Remodeling may be triggered by factors such as exercise, sedentary lifestyle, and changes in diet.
25. What are some of the important functions of calcium in the body? ANSWER: Heartbeat, respiration, nerve cell functioning, enzyme functioning, and blood clotting are all processes that depend on proper levels of calcium.
26. What types of mechanical stress may be used to strengthen bone tissue? ANSWER: Basically it's just exercise. Moderate weight lifting or walking stresses bones, which help build and retain bone mass. If bones are not being used, then they will lose their mass.
27. How does aging affect the brittleness of bone and the loss of bone mass? ANSWER: Bone brittleness results from a decrease in the rate of protein synthesis and in the production of human growth hormone, which diminishes the production of the collagen fibers that give bone its strength and flexibility. As a result, inorganic minerals gradually constitute a greater proportion of the bone extracellular matrix. Loss of bone mass results from demineralization and usually begins after age 30 in females, accelerates greatly around age 45 as levels of estrogens decrease, and continues until as much as 30% of the calcium in bones is lost by age 70
28. What factors determine movement at joints?
ANSWER: (1) the shape of the articulating bones, (2) the flexibility (tension or tautness) of the ligaments that bind the bones together, and (3) the tension of associated muscles and tendons.
29. Define each of the movements at synovial joints and give an example of each. ANSWER: Gliding: is a simple movement in which relatively flat bone surfaces move back-and-forth and side-to-side relative to one another. This can be illustrated between the clavicle and acromion of the scapula by placing your upper limb at your side, raising it above your head, and lowering it again. Angular Movements: there is an increase or a decrease in the angle between articulating bones. Flexion there is a decrease in the angle between articulating bones.( Examples of flexion include bending the head toward the chest) Extension there is an increase in the angle between articulating bones.( Extension is simply the reverse of these movements.) Hyperextension Continuation of extension beyond the anatomical position.( Examples of hyperextension include bending the head backward; moving the humerus backward, as in swinging the arms backward while walking ) Abduction is the movement of a bone away from the midline.( Examples of abduction include lateral movement of the humerus upward) Adduction is the movement of a bone toward the midline.( such as bringing arms to side from extended position at shoulder) Circumduction is movement of the distal end of a part of the body in a circle.( Examples of joints that allow circumduction include the humerus at the shoulder joint (making a circle with your arm) and the femur at the hip joint (making a circle with your leg) Rotation a bone revolves around its own longitudinal axis.( An example is turning the head from side to side, as in signifying “no”) Special Movements which occur only at certain joints, include elevation, depression, protraction, retraction, inversion, eversion, dorsiflexion, plantar flexion, supination, and pronation. Depression the downward movement of a part of the body, such as opening the mouth to depress the mandible or returning shrugged shoulders to the anatomical position to depress the scapula.
Protraction is the movement of a part of the body forward. You can protract your mandible by thrusting it outward or protract your clavicles by crossing your arms.
Retraction is the movement of a protracted part of the body back to the anatomical position
Inversion is movement of the soles medially so that they face each other.
Eversion is movement of the soles laterally so that they face away from each other.
Dorsiflexion is bending of the foot in the direction of the dorsum (superior surface), as when you stand on your heels.
Plantar flexion involves bending of the foot in the direction of the plantar surface as when standing on your toes.
Supination is movement of the forearm so that the palm is turned forward.Supination of the palms is one of the defining features of the anatomical position.
Pronation is movement of the forearm so that the palm is turned backward.
30. Which joints show evidence of degeneration in nearly all individuals as aging progresses? ANSWER: almost everyone develops some type of degeneration in the knees, elbows, hips, and shoulders. It is also common for elderly individuals to develop degenerative changes in the vertebral column, resulting in a hunched-over posture and pressure on nerve roots. One type of arthritis, called osteoarthritis, is at least partially age related.
31. Which features distinguish the three types of muscular tissue? ANSWER: Skeletal: It is striated; that is, striations, or alternating light and dark protein bands, are visible under a microscope. Because skeletal muscle can be made to contract and relax by conscious control, it is voluntary Due to the presence of a small number of cells that can undergo cell division, skeletal muscle has a limited capacity for regeneration Cardiac: found only in the heart, forms the bulk of the heart wall. The heart pumps blood through blood vessels to all parts of the body. Like skeletal muscle tissue, cardiac muscle tissue is striated. However, unlike skeletal muscle tissue, it is involuntary. Its contractions are not under conscious control. Cardiac muscle can regenerate under certain conditions Smooth: is located in the walls of hollow internal structures, such as blood vessels, airways, the stomach, and the intestines. Smooth muscle is nonstriated (lacks striations) and involuntary (not under conscious control). Although smooth muscle tissue has considerable capacity to regenerate when compared with other muscle tissues, this capacity is limited when compared to other types of tissues, for example, epithelium.
32. What are the general functions of muscular tissue?
ANSWER: producing body movements, stabilizing body positions, storing and moving substances within the body, and producing heat
33. What is a sarcomere? What does a sarcomere contain?
ANSWER: Sarcomere the basic functional units of striated muscle fibers.The thick filament system is composed of Myosin protein, which is connected from the M-line to the Z-disc bytitin. It also contains myosin-binding protein C, which binds at one end to the thick filament and the other to Actin.The thin filaments are assembled by Actin monomers bound to nebulin, which also involves tropomyosin (a dimer that coils itself around the F-actin core of the thin filament) and troponin. Nebulin and titin give stability and structure to the sarcomere.
34. Explain how a skeletal muscle contracts and relaxes.
ANSWER: Before a skeletal muscle fiber can contract, it must be stimulated by an electrical signal called a muscle action potential delivered by its neuron called a motor neuron. A single motor neuron along with all the muscle fibers it stimulates is called a motor unit. Stimulation of one motor neuron causes all the muscle fibers in that motor unit to contract at the same time. Muscles that control small, precise movements, such as the muscles that move the eyes, have 10 to 20 muscles fibers per motor unit. Muscles of the body that are responsible for large, powerful movements, such as the biceps brachii in the arm and gastrocnemius in the leg, have as many as 2000 to 3000 muscle fibers in some motor units. As the axon (long process) of a motor neuron enters a skeletal muscle, it divides into branches called axon terminals that approach—but do not touch—the sarcolemma of a muscle fiber. The ends of the axon terminals enlarge into swellings known as synaptic end bulbs, which contain synaptic vesicles filled with a chemical neurotransmitter. The region of the sarcolemma near the axon terminal is called the motor end plate. The space between the axon terminal and sarcolemma is the synaptic cleft. The synapse formed between the axon terminals of a motor neuron and the motor end plate of a muscle fiber is known as the neuromuscular junction (NMJ). At the NMJ, a motor neuron excites a skeletal muscle fiber in the following way: Release of acetylcholine. Arrival of the nerve impulse at the synaptic end bulbs triggers release of the neurotransmitter acetylcholine (ACh). ACh then diffuses across the synaptic cleft between the motor neuron and the motor end plate. Activation of ACh receptors. Binding of ACh to its receptor in the motor end plate opens ion channels that allow small cations, especially sodium ions (Na+), to flow across the membrane. Activation of ACh receptors. Binding of ACh to its receptor in the motor end plate opens ion channels that allow small cations, especially sodium ions (Na+), to flow across the membrane. Activation of ACh receptors. Binding of ACh to its receptor in the motor end plate opens ion channels that allow small cations, especially sodium ions (Na+), to flow across the membrane. Generation of muscle action potential. The inflow of Na+ (down its concentration gradient) generates a muscle action potential. The muscle action potential then travels along the sarcolemma and through the T tubules. Each nerve impulse normally elicits one muscle action potential. Breakdown of ACh. The effect of ACh lasts only briefly because the neurotransmitter is rapidly broken down in the synaptic cleft by an enzyme called acetylcholinesterase (AChE).
35. What is the importance of the neuromuscular junction?
ANSWER: Includes the axon terminal of a motor neuron plus the motor end plate of a muscle fiber. Is where the axons of motor nerves meet the muscle & transmit messages from the brain which cause the muscle to contract & relax
36. Define the following terms: myogram, twitch contraction, wave summation, unfused tetanus, and fused tetanus. ANSWER: Myogram a graphical recording of muscle activity. twitch contraction is a brief contraction of all the muscle fibers in a motor unit in response to a single action potential in its motor neuron. wave summation This phenomenon, in which stimuli arriving one after the other before a muscle fiber has completely relaxed and causes larger contractions. unfused tetanus When a skeletal muscle fiber is stimulated at a rate of 20 to 30 times per second, it can only partially relax between stimuli. fused tetanus When a skeletal muscle fiber is stimulated at a higher rate of 80 to 100 times per second, it does not relax at all.
37. What characteristics distinguish the three types of skeletal muscle fibers? ANSWER: Slow oxidative (SO) fibers or red fibers are small in diameter and appear dark red because they contain a large amount of myoglobin. Because they have many large mitochondria, SO fibers generate ATP mainly by aerobic cellular respiration, which is why they are called oxidative fibers. These fibers are said to be “slow” because the contraction cycle proceeds at a slower pace than in “fast” fibers. SO fibers are very resistant to fatigue and are capable of prolonged, sustained contractions. Fast oxidative–glycolytic (FOG) fibers are intermediate in diameter between the other two types. Like slow oxidative fibers, they contain a large amount of myoglobin, and thus appear dark red. FOG fibers can generate considerable ATP by aerobic cellular respiration, which gives them a moderately high resistance to fatigue. Because their glycogen content is high, they also generate ATP by anaerobic glycolysis. These fibers are “fast” because they contract and relax more quickly than SO fibers. Fast glycolytic (FG) fibers or white fibers are largest in diameter, contain the most myofibrils, and generate the most powerful and most rapid contractions. They have a low myoglobin content and few mitochondria. FG fibers contain large amounts of glycogen and generate ATP mainly by anaerobic glycolysis. They are used for intense movements of short duration, but they fatigue quickly. Strength-training programs that engage a person in activities requiring great strength for short times produce increases in the size, strength, and glycogen content of FG fibers.
38. Explain how the characteristics of skeletal muscle fibers may change with exercise. ANSWER: Endurance-type (aerobic) exercises, such as running or swimming, cause a gradual transformation of some FG fibers into fast oxidative–glycolytic (FOG) fibers. The transformed muscle fibers show slight increases in diameter, number of mitochondria, blood supply, and strength. Endurance exercises also result in cardiovascular and respiratory changes that cause skeletal muscles to receive better supplies of oxygen and nutrients but do not increase muscle mass. By contrast, exercises that require great strength for short periods produce an increase in the size and strength of FG fibers. The increase in size is due to increased synthesis of thick and thin filaments. The overall result is muscle enlargement (hypertrophy), as evidenced by the bulging muscles of body builders.
39. Why does muscle strength decrease with aging?
ANSWER: humans undergo a slow, progressive loss of skeletal muscle mass that is replaced largely by fibrous connective tissue and adipose tissue. In part, this decline is due to decreased levels of physical activity. Accompanying the loss of muscle mass is a decrease in maximal strength, a slowing of muscle reflexes, and a loss of flexibility. In some muscles, a selective loss of muscle fibers of a given type may occur. With aging, the relative number of slow oxidative fibers appears to increase. This could be due either to atrophy of the other fiber types or their conversion into slow oxidative fibers.
40. What are the functions of the dendrites, cell body, axon, and synaptic end bulbs of a neuron? ANSWER: The cell body contains a nucleus surrounded by cytoplasm that includes typical organelles such as rough endoplasmic reticulum, lysosomes, mitochondria, and a Golgi complex. Most cellular molecules needed for a neuron's operation are synthesized in the cell body. dendrites (= little trees) are the receiving or input parts of a neuron. Usually, dendrites are short, tapering, and highly branched, forming a tree-shaped array of processes that emerge from the cell body. the axon, conducts nerve impulses toward another neuron, a muscle fiber, or a gland cell. The tips of most axon terminals swell into synaptic end bulbs. These bulb-shaped structures contain synaptic vesicles, tiny sacs that store chemicals called neurotransmitters. The neurotransmitter molecules released from synaptic vesicles are the means of communication at a synapse.
41. Which cells produce myelin in nervous tissue, and what is the function of a myelin sheath? ANSWER: Schwann cells produce myelin and wrap it around a single nerve cell axon. A myelin sheath is a protective layer that develops over nerves in the central nervous and peripheral nervous systems.
42. What are the meanings of the terms: resting membrane potential, depolarization, repolarization, nerve impulse, and refractory period? ANSWER: When muscle fibers and neurons are “at rest” (not conducting action potentials), the voltage across the plasma membrane is termed the resting membrane potential. During the depolarizing phase, the negative membrane potential becomes less negative, reaches zero, and then becomes positive. Then, during the repolarizing phase, the membrane polarization is restored to its resting state of -70 mV. nerve impulse : The signal that travels along the length of a nerve fiber and ends in the release of neurotransmitters. refractory period A brief period of time following the stimulation of a nerve during which the nerve will not.
43. What is the significance of the blood-brain barrier?
ANSWER: The existence of a blood–brain barrier (BBB) protects brain cells from harmful substances and pathogens by preventing passage of many substances from blood into brain tissue. This barrier consists basically of very tightly sealed blood capillaries (microscopic blood vessels) in the brain.
44. Why is the hypothalamus considered part of both the nervous system and the endocrine system? ANSWER: The hypothalamus is the main link between the endocrine and nervous systems. Controls and integrates activities of the autonomic nervous system and pituitary gland. Regulates emotional and behavioral patterns and circadian rhythms. Controls body temperature and regulates eating and drinking behavior. Helps maintain waking state and establishes patterns of sleep 45. Where are the primary somatosensory area and primary motor area located in the brain? What are their functions? ANSWER: The primary somatosensory area is posterior to the central sulcus of each cerebral hemisphere in the postcentral gyrus of the parietal lobe. It receives nerve impulses for touch, proprioception (joint and muscle position), pain, itching, tickle, and temperature and is involved in the perception of these sensations. The primary somatosensory area allows you to pinpoint where sensations originate, so that you know exactly where on your body to swat that mosquito. the primary motor area is located in the precentral gyrus of the frontal lobe in each hemisphere. each region in the primary motor area controls voluntary contractions of specific muscles on the opposite side of the body.
46. What happens during the fight-or-flight response?
ANSWER: During the fight-or-flight response, your body provides you with energy, reflexes, and strength you may need to respond to the stressor. As past of the fight-or-flight response, your body releses epinephrine formerly called andrealine, is one of the hormones that are released by the body in times of stress. Epinephrine prepares the body for quick action by triggering the changes.Your breathing speeds up, which helps get more oxygen throughout your body.Your heart beats faster, which increases the flow of blood to carry more oxygen to your muscles.Your muscles tense up, which prepares you to move quickly.the pupils of your eyes get wider, which allows extra light for more sensitive vision.Your digestion slows down, because digestion is an unneccssary activity during an emergency.Blood sugar increases to provide more fuel for fighting.
47. Why is the parasympathetic division of the ANS considered the rest-and-digest division? ANSWER: It is called the rest and digest system because this is exactly what theparasympathetic nervous system controls. There are two branches of the autonomic nervous system (ultimately, there are two branches of the human nervous system, the autonomic branch, as previously mentioned, (and a branch that is not under our voluntary control) and the somatic nervous system (which is under our voluntary control)). The divisions of the autonomic nervous system include the symathetic and the parasympathetic branches. The parasympathetic branch is in charge of all bodily functions not under voluntary control that would normally be taking place in a relaxed, tranquil environment. When relaxed, the parasympathetic division stimulates our digestive system to become active and propel foodstuffs along the alimentary tract in order to provide nutrients to our body
48. Which senses are “special senses”?
ANSWER: smell, taste, vision, hearing, and balance.
49. Why is it beneficial to your well-being that nociceptors and proprioceptors exhibit very little adaptation? ANSWER: nociceptors perceive pain and proprioceptors perceive muscle length, muscle tension, and joint position and movement
50. What is referred pain, and how is it useful in diagnosing internal disorders? ANSWER: visceral pain is the fact that it is often felt in places remote from the location of the affected organ. This is known as 'referred pain' and it is often a very useful tool to diagnose diseases of internal organs.Many people know that cardiac ischaemia produces pain in the left part of the chest and even in the left arm and hand. This is referred cardiac pain, a sensation felt in an otherwise normal part of the body but that it is due to a poor oxygen supply to the heart.Similar patterns of referred pain can be detected in diseases of the gut, the bladder or the internal genital organs, where the pain is felt in the abdomen, the pelvic region or the back, with the patient not being able to locate the pain very accurately.