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BSC 105Muscles
| Question | Answer |
|---|---|
| Ability for muscles to contract | Contractility |
| 4 major characteristics of muscle contraction? | Contractility, excitability, extensibility, and elasticity |
| What is the most superficial layer of a muscle? | Fascia |
| What is the capacity of skeletal muscle to respond to a stimulus? | Excitability |
| What is the ability to be stretched? | Extensibility |
| What is the ability to recoil to their original length after stretching? | Elasticity |
| Connective tissue sheath around the skeletal muscle? | Epimysium |
| Muscle cells | Muscle fibers |
| What shape is each muscle fiber? | Cylindrical |
| What does each muscle fiber contain? | Several nuclei |
| What are the numerous bundles that make up muscles called? | Fasciculi |
| What surrounds each individual muscle fiber? | Endomysium |
| What are myofibrils? | Threadlike structures that fills the cytoplasm |
| What are the 2 major protein fibers? | Actin Myofilaments and Myosin myofilaments |
| Which myofilament is thinner? Actin or myosin? | Actin |
| Which myofilament is thicker? Actin or myosin? | Myosin |
| What does actin resemble? | 2 minute strands of pearls twisted together |
| What does myosin resemble? | Bundles of minute golf clubs |
| What does actin and myosin form? | Sarcomeres |
| What is the basic structural and functional unit of the muscle? | Sarcomeres |
| What defines a sarcomere? | Z line to Z line |
| What does the I band consist of? | Actin |
| What is the loose connective tissue sheath that surrounds the fasciculi called? | Perimysium |
| How does the arrangement of actin and myosin affect the appearance of sacromeres? | Banded appearance |
| What is found on each side of the Z line? | I band |
| What is the A band? | The darker central region in the central region of each sacromere |
| What does the A band consist of? | Myosin |
| What is the light zone in the center of each sarcomere? | H zone |
| What does the H zone consist of? | Only Myosin |
| What is the dark staining line in the center of the sarcomere? | M line |
| Where are the myosin myofilaments anchored at? | M line |
| How is the outside of the cell membrane charged compared to the inside? | Positively |
| How is the inside of the cell membrane charged? | Negatively |
| What is the charge difference across the membrane called? | Resting membrane potential |
| What happens to a muscle cell when it is stimulated? | Characteristics change briefly |
| What is the brief reversal back of the charge called? | Action potential |
| What are nerve cells that carry action potentials to skeletal muscle fibers? | Motor neurons |
| What enters the muscles and branch? | Axons |
| What does each axon branch that connects to the muscle form? | Neuromuscular junction (synapse) |
| Where does a neuromuscular junction (synapse) form? | Center of the cell |
| What is a single motor neuron and all the skeletal muscle fibers it innervates called? | Motor unit |
| How is a neuromuscular junction formed? | Enlarged nerve terminal resting in an indentation of the muscle cell membrane |
| What is the enlarged nerve terminal called? | Presynaptic terminal |
| What is the space between the presynaptic terminal and the muscle cell? | Synaptic cleft |
| What does each presynaptic terminal contain? | Synaptic vesicles |
| What do synaptic vesicles secrete? | Acetylcholine |
| What does acetylcholine diffuse across? | Synaptic cleft |
| What does acetylcholine do when it binds to the postsynaptic terminal? | Causes change in postsynaptic cell |
| What happens when action potential reaches the nerve terminal? | Synaptic vesicles release acetylcholine into the synaptic cleft by exocytosis |
| The acetylcholine diffuses across the synaptic cleft in order to do what? | Bind to receptor molecules in the muscle cell membrane (sarcolemma) |
| What is another name for the muscle cell membrane? | Sarcolemma |
| What does the combination of acetylcholine and its receptor cause? | An increase of sodium ions |
| What does this influx initiate in the muscle cell? | Action potential, causing it to contract |
| What happens to the acetylcholine when it is released back into the synaptic cleft between the neuron and muscle cell? | Rapidly broken down by enzymes |
| What enzyme breaks down acetylcholine? | Acetylcholinesterase |
| What does the enzymatic breakdown ensure? | One action potential in the neuron yields only one action potential in the skeletal muscle, and only one contraction of skeletal muscle |
| When does muscle contraction occur? | As actin and myosin are sliding past each other causing the sarcomeres to shorten |
| What happens when the sarcomeres shorten? | The muscle shortens |
| What is the sliding of actin myofilaments past myosin myofilaments during contraction called? | Sliding filament mechanism |
| Which bands in the sarcomeres get shorter when the muscles contract? | H and I bands only |
| True/False: The A band shorten during muscle contraction. | False |
| What is a muscle twitch? | Contraction of of an entire muscle in response to a stimulus that causes action potential in one or more muscle fibers |
| What is a muscle fiber that will not respond to a stimulus until that stimulus reaches a threshold that causes it to contract maximally called? | All-or-nothing response |
| What is the time between application of a stimulus to a motor neuron and the beginning of a contraction called? | Lag phase |
| What is the time of contraction called? | Contraction phase |
| What is the time during which the muscle relaxes called? | Relaxation phase |
| What is the condition where the muscles remain contracted without relaxing called? | Tetany |
| What is the increase in number of motor neurons being activated called? | Recruitment |
| If successive stimuli are given, what will happen to the muscle? | It will contract so frequently it won't have time to relax, which could lead to tetany |
| What is ATP? | Adenosine triphosphate |
| What is needed for energy for muscle contractions? | ATP |
| Where is ATP produced? | Mitochondria |
| How long does ATP last? Is it stable? | ATP is short-lived and unstable |
| What does ATP degenerate to in order to become more stable? | ADP plus a phosphate |
| What does ADP stand for? | Adenosine diphosphate |
| What do muscle cells have to constantly produce? | ATP |
| Can ATP be stockpiled or stored when at rest? | No |
| What high-energy molecule can be stored? | Creatine phosphate |
| What is energy molecules in ATP used to synthesize during periods of inactivity? | Creatine phosphate |
| What can be accessed quickly during periods of activity and be used to produce ATP to be used in muscle contraction? | Creatine phosphate |
| What is anaerobic respiration? | Without oxygen |
| What is aerobic respiration? | With oxygen |
| Which is more efficient? Anaerobic or aerobic respiration? | Aerobic |
| Why does breathing rate stay elevated for a short time after exercising even though the muscles are not actively contracting? | Pay back the oxygen debt |
| What is the oxygen debt? | Amount of oxygen needed to convert lactic acid to glucose and replenishes depleted creatine phosphate stores |
| How does muscle fatigue occur? | ATP is used during muscle contraction faster than it can be produced |
| What are the 2 types of muscle contractions? | Isotonic and isometric |
| What is isotonic muscle contractions? | Equal tension-Tension produced is constant, but the length changes |
| What is isometric contractions? | Equal distance- The length of the muscle does not change, but the tension changes |
| What does "Muscle tone" refer to? | Constant tension produced by muscles for long periods of time; keeps head up and back straight |
| What are fast=twitch fibers? | Muscles that contract and fatigue quickly; adapted to anaerobic processes |
| What is an example of a fast-twitch muscle? | White meat of a chicken breast |
| What are slow-twitch fibers? | Contract more slowly and more resistant to fatigue; better suited to aerobic processes |
| What is an example of a slow-twitch fiber? | Dark meat of a duck breast or the legs of a chicken |
| What are the points of attachment for muscles? | Origin and Insertion points |
| What connects that muscle to the body at these points? | Tendons |
| What is the origin of a muscle? | The most stationary part (head) of a muscle |
| What is the insertion point of a muscle? | End undergoing the greatest movement |
| What is the portion of the muscle between the origin and insertion called? | Belly |
| Can muscles have more than one head or origin? | Yes, some muscles have multiple heads or origins |
| What are muscles that work together to accomplish specific movements called? | Synergists |
| What are muscles that work in opposition to one another called? | Antagonists |
| If one muscle plays a major role in accomplishing the desired movement among synergists, what is it called? | Prime mover |
| How are muscles named? | Descriptively; some include location, size, orientation of fibers, shape, origin, insertion, and function |
| What muscle raises the eyebrows? | Occipitofrontalis |
| What muscle closes the eyelids and cause "crows feet" wrinkles in the skin at the corners of the eye> | Orbicularis oculi |
| What muscle puckers the lips? | Orbicularis oris |
| What flatten's the cheeks and is also called the trumpeters muscle? | Buccinator |
| What is the smiling muscle? | Zygomaticus |
| What is the sneering muscle? | Levator labii superioris |
| What is the frowning muscle? | Depressor anguli oris |
| What is another name for chewing? | Mastication |
| How many pairs of mastication muscles do we have? | 4 |
| What are the 4 pairs of mastication muscles? | 2 pairs of pterygoids, temporalis, and masseter |
| What does the intrinsic tongue muscles do? | Change the shape of the tongue |
| What does the extrinsic tongue muscles do? | Move the tongue |
| What is the lateral neck muscle and prime mover? | Sternocleidomastoid |
| What movement does it allow? | Rotates and abducts the head |
| What is the group of muscles on each side of the back? | Erector spinae |
| What are the erector spinae responsible for? | Keeping the back straight and the body erect |
| What are the muscles that move the thorax? | Thoracic muscles |
| Which two muscles are the most involved in breathing? | External intercostals and internal intercostals |
| What do the external intercostals do? | Elevate the ribs during inspiration |
| What do the internal intercostals do? | Contract during forced expiration |
| What does the diaphragm do? | Accomplishes quiet breathing; aids in breathing |
| What shape is the diaphragm? | Dome-shaped |
| What are the hamstring muscles? | Posterior thigh muscles |
| What does the hamstring do? | Flexes the leg and extends the thigh |
| What two muscles form the calf muscle? | Gastrocnemius and soleus |
| What tendon does the joined gastrocnemius and soleus form? | Achiles |
| What does the achilles do? | Flexes the foot and toes |
| What are the lateral muscles of the leg called? | Peroneus muscles |
| What are peroneus muscles primarily responsible for? | Turning the foot outward |
| What is one other thing that the peroneus muscles aid in? | Plantar flexion |
| How many muscles are located in the foot? | 20 |
| What are the foot muscles called? | Intrinsic foot muscles |
| What do the intrinsic foot muscles do? | Flex, extend, abduct, and adduct the toes |
| What does the trapezius muscles do? | Rotate the scapula |
| What does the Serratus anterior muscle do? | Pulls scapula anteriorly |
| What muscles attaches the arms to the body? | Pectoralis major and latissimus dorsi muscles |
| What movements does the pectoralis major allow? | Adducts and flexes the arm |
| What movements does the latissimus dorsi allow? | Medially roatates, adducts, and powerfully extends the arm |
| What is another name for the latissimus dorsi? | Swimmer muscles |
| What attaches the humerus to the scapula and clavicle? | Deltoid |
| What is the major abductor of the upper limb? | Deltoid |
| What does the triceps brachii muscle do? | Extends the forearm |
| Where is the triceps brachii located? | Posterior compartment of the arm |
| What does the biceps brachii do? | Flexes the forearm |
| Where is the biceps brachii located? | Anterior compartment of the arm |
| What does brachialis do? | Flexes forearm |
| What does the brachiordialis do? | Flexes and supinates the forearm |
| What does the flexor carpi do? | Flexes the wrist |
| What does the extensor carpi do? | Extends the wrist |
| What does the flexor digitorium do? | Flexes the fingers |
| What does the extensor digitorium do? | Extends the fingers |
| What are the hand muscles called? | Intrinsic hand muscles |
| What muscle is responsible for the abduction and adduction of the fingers? | Interossi muscles |
| How many intrinsic hand muscles do we have? | 19 |
| Where are the interossi muscles located? | Between the metacarpals |
| What is the strong band of fibrous connective tissue that covers the flexor and extensor tendons and holds them in place around the wrist so they don't bowstring during muscle contraction? | Retinaculum (bracelet) |
| What is the gluteus maximus? | Buttocks |
| What is the gluteus medius? | Hip muscle and common injection site |
| What contributes most of the mass to the buttocks? | Gluteus maximus |
| What muscle extends the leg? | Quadriceps femoris |
| Where is the quadriceps femoris? | Anterior thigh muscles |
| What is the sartorius? | Tailors muscle |
| What does the sartorius do? | Flexes the thigh |
| What motions is the muscles of the anterior abdominal wall responsible for? | Flexes and rotates the vertebral column, compresses the abdominal cavity, and holds in the abdominal viscera |
| What is visible in the person visible in a person with relatively little fat? | Vertical linear indentation |
| How far does the vertical linear indentation stretch? | From the sternum, through the navel, to the pubis |
| What is the tendinous area of the abdominal wall that the vertical linear indentation strecth through called? | Linea alba |
| What does the linea alba consist of instead of muscle? | White connective tissue |
| What is found on each side of the linea alba? | Rectus abdominus |
| What crosses the rectus abdominus at three or more locations, making a muscled person appear segmented (abs)? | Tendinous inscriptions |
| What is lateral to the rectus abdominus? | Layers of muscle |
| What are the muscles lateral to the rectus abdominus from superficial to deep? | External abdominal oblique, internal abdominal oblique, and transverse abdominis muscle |
| How are the fasciculi of the 3 muscle layers oriented? | In opposite directions of each |
| What happens when these muscles contract? | They compress the abdominal contents |
| About how many taste buds do adults have? | About 4,000 |
| What are the 5 major taste receptors? | Sweet, salty, sour, bitter, and umami |
| About what percent of what we taste is actually due to our sense of smell? | 80%-90% |
| What does our sense of smell depend on? | 10 to 20 million olfactory cells |
| Where are our olfactory cells located at? | Olfactory epithelia high in the roof of the nasal cavity |
| What are olfactory cells? | Modified neurons |
| What are the 3 layers of the eye? | Sclera, choroid, and retina |
| What is the superficial (outer) layer of the eye? | Sclera |
| What is the white of our eyes? | Sclera |
| What is the cornea made up of? | Transparent collagen fibers |
| What is the cornea also known as? | The window of our eye |
| What is the only organ that can be transplanted without taking rejection medicine? | Cornea |
| What is the thin, middle coat of the eye? | Choroid |
| What does the choroid have? | Extensive blood supply |
| What does the dark pigments of the choroid absorb? | Stray light rays |
| What is found in the choroid layer and regulates the size of the pupil? | Iris |
| What is the colored portion of the eye? | Iris |
| What is found behind the iris? | Ciliary body containing ciliary muscle |
| What does ciliary body control? | Shape of the lens |
| What attaches the lens to the ciliary body? | Suspensory ligaments |
| What does the lens attachment do for the eye? | Divides it into two compartments |
| What is the anterior compartment of the eye filled with? | Aqueous fluid |
| How much aqueous fluid is made daily? How does it leave? | A small amount and leaves through tiny ducts |
| What occurs when the tiny aqueous ducts become blocked? | Glaucoma |
| What can glaucoma lead to? | Total blindness |
| What is the third and deep layer of the eye? | Retina |
| Which compartment is the retina located in? | Posterior compartment |
| What fills the posterior compartment? | Clear, gelatinous fluid called vitreous humor |
| What does the vitreous humor do? | Holds the retina in place and supports the lens |
| What are the two photoreceptors in the retina called? | Rods and cones |
| What controls our peripheral vision? Can they detect color? | Rods; no they don't collect color |
| What controls our center vision? Can they detect color? | Cones; Yes they collect color |
| What do sensory fibers from the retina form? | Optic nerve |
| What part of the eye collects nerve signals from the brain? | Optic nerve |
| How is the blind spot described? | No rods or cones at the optic nerve |
| Is vision possible in the blind spot? | No, it's the blind spot for a reason |
| What are 4 abnormalities of the eye | Colorblindness, nearsightedness, farsightedness, and astigmatism |
| What is colorblindness? | You cannot see certain colors |
| What is the most common colorblindness? | red-green colorblindness |
| Are males or females more susceptible to colorblindness? | Males, it is on the X chromosome |
| What is nearsightedness? | You can see up close, but not far away |
| What is farsightedness? | Can see far away, but not up close |
| What is astigmatism? | Light is not evenly focused on the retina |
| What are some causes for astigmatism? | The cornea or lens is uneven, making the image fuzzy |
| What are the 3 divisions of the ear? | Outer, middle, and inner |
| What does the outer division of the ear consist of? | Pinna (external flap) and auditory canal |
| What lines the auditory canal? | Fine hairs and sweat glands |
| What is located in the upper wall of the auditory canal? | Modified sweat glands |
| What do modified sweat glands secrete? | Earwax |
| What does earwax do? | Substance that guards the ear against the entrance of foreign materials; air pollutants |
| Where does the middle division of the ear begin and end? | Begins-Tympanic membrane (eardrum) Ends-oval and round windows |
| What is the bony wall containing two small opening covered by membranes in the ear? | Oval and Round windows |
| What are the three small bones found between the tympanic membrane and oval window called? | Ossicles |
| What are the names of the 3 bones found between the tympanic membrane and oval window? | Malleus (hammer), incus (anvil), and stapes (stirrups) |
| What does the names of the 3 bones reveal? | Their actual shapes |
| Where does the auditory (Eustachian tubes) extend to? | Middle ear to nasopharynx |
| What does the Eustachian tubes do? | Equalize air pressure |
| What fills the middle and outer air? | Air |
| What fills the inner ear? | Fluid |
| What are the 3 areas of the inner ear? | Semicircular canals, vestibule, and cochlea |
| What does the semicircular canals and vestibule deal with? | Equilibrium |
| What does the cochlea deal with? | Hearing |
| What shape does the cochlea resemble? | Snail's shell |
| What does the CNS (Central Nervous System) consist of? | Brain and spinal cord |
| What does the PNS (Peripheral Nervous System) consist of? | Nerves and their receptors, synapsis, and ganglia that lie outside the CNS |
| What does the afferent division transmit? | Action potentials from sensory organs to the CNS |
| What does the efferent division transmit? | Action potentials from the CNS to the effector organs, such as muscles and glands |
| What does the somatomotor nervous system transmit? | Impulses from CNS to skeletal muscle |
| What does the autonomic nervous system transmit? | Transmits action potentials from the CNS to smooth muscle, cardiac muscle, and glands |
| What are nerve cells? | Neurons |
| What do neurons do? | Receive stimuli and transmit action potentials to other neurons or to effector organs |
| What does a neuron consist of? | Cell body and 2 types of processes: Dendrites and Axons |
| How many nuclei does each neuron cell body contain? | One |
| What is the function of dendrites? | Receive information from other neurons or sensory receptors and carry the information to the cell body |
| What are dendrites? | Short, highly branching cytoplasmic extensions that are tapered from their cell body to their tips. Most are extensions of the cell body |
| What is the function of axons? | Carry information away from the cell body |
| What surrounds most axons? | Myelin sheath |
| What can axons do structurally? | Remain single or branch to form a collateral axon |
| What is neuroglia? What is another name for it? | Nerve glue; glial cells |
| Are neuroglia more numerous than neurons? | Yes, they are more numerous |
| What forms the myelin sheath around the axons? | Schwann cells |
| What is the gap between Schwann cells called? | Nodes of Ranvier |
| Are axons either completely covered or partially covered by myelin sheaths? | Both |
| What do groups of nerve cell bodies and their dendrites form? | Gray matter |
| What is gray matter on the surface of the brain called? | Cortex |
| What are gray matter clusWhat are ters deep within the brain called? | Nuclei |
| What are bundles of axons and their connective tissue sheaths called in the PNS? | Nerves |
| Where is the brain housed? | Cranial vault |
| What are the 4 major regions of the brain? | Brainstem, dencephalon, cerebellum, and cerebrum |
| What 3 structures make up the brainstem? | Medulla Oblongata, pons, and midbrain |
| What does the brainstem do? | Connects the spinal cord to the remainder of the brain and is responsible for many functions. |
| What does damage to the brainstem often result in? | Death |
| What is the medulla oblongata? | Most inferior part of the brain and is continuous with the spinal cord |
| What are some functions of the medulla oblongata? | Regulate heart rate, blood vessel diameter, breathing, swallowing, vomiting, coughing, sneezing, balance, and coordination |
| What are the 2 prominent enlargements that extend the length of the medulla called? | Pyramids |
| What are pons? Where is it located compared to the medulla oblongata? | Bridge-superior to the medulla oblongata |
| What do pons do? | Relay information |
| Where are pons located? (In general) | Between the cerebrum and cerebellum |
| What does "bridge" describe for pons? | Structure and function |
| Where is the midbrain located compared to the pons? | Superior to the pons |
| What does the midbrain consist of? | 4 mounds called colliculi |
| What are colliculi involved in? | Hearing and visual reflexes |
| What is reticular formation? | Scattered nuclei that play a role in the sleep/wake cycle |
| How do general anesthetics function? | They suppress the reticular formation |
| What could damage to the reticular formation cause? | Coma |
| What can the removal of visual or auditory stimuli lead to? | Drowsiness |
| What is the dencephalon? | Part of brain between the brainstem and cerebrum |
| What are the components of the dencephalon? | Thalamus, pineal body, and hypothalamus |
| What is the largest portion of the dencephalon? | Thalamus |
| What shape is the thalamus? | Yo-yo shaped |
| What does the thalamus do? | Registers an unconscious, unlocalized, uncomfortable perception of pain |
| Where is the pineal body located compared to the thalamus? | Posteriorly |
| What type of gland is the pineal body? | Endocrine gland |
| What shape is the pineal body? | Pine-cone shaped |
| What can the pineal body influence? | The onset of puberty |
| What is another major thing the pineal body may play a role in? | Hibernation |
| What is the most inferior part of the diencephalon | Hypothalamus |
| What is the hypothalamus important in maintaining? | Homeostasis |
| What does the hypothalamus play a central role in? | Control of body temp., hunger, thirst, good feelings, rage, fear, etc. |
| What is the funnel-shaped stalk that extends from the floor of the hypothalamus to the pituitary gland? | Infundibulum |
| What do the mammilary bodies involve? | Olfactory reflexes |
| What do mammilary bodies gather and control? | Emotional responses to odors and memory |
| What si the largest portion of the brain? | Cerebrum |
| What is the cerebrum divided into? | Left and right hemispheres by a longitudinal fissure |
| What are the numerous fold that greatly increase the surface area of the cortex? | Gyri |
| What is the intervening grooves of the cerebrum? | Sulci |
| What is each hemisphere of the cerebrum divided into? | Lobes |
| How are the lobes of the cerebrum named? | For the bones that are over them |
| What are the 4 lobes of the cerebrum? | Frontal lobe, Parietal lobe, occipital lobe, and temporal lobes |
| What is the frontal lobe important in? | Voluntary motor function, motivation, agression, and mood |
| What is the parietal lobe the principal center for? | Reception and evaluation of most sensory info such as touch, balance, and taste |
| What does the occipital lobe function in? | Reception and integration of visual input and is not distinctly separate from other lobes |
| What does the temporal lobe evaluate? | Olfactory and auditory input |
| What is the temporal lobe important in? | Memory; abstract thought and judgement |
| What are the 3 types of memory? | Sensory, short-term, and long-term |
| How long does sensory memory retain information? | Less than a second |
| How long does short-term memory retain information? | Few seconds to a few minutes |
| Can sensory memory become short or long-term memory? | Yes, but only if it is valuable |
| What is sensory memory described as? | Brief retention of sensory input as it is scanned, evaluated, and acted upon |
| How long does short-term memory last | About 30 minutes |
| How many bits of information is short-term memory usually limited to? | About 7 bits of information |
| What can happen to large amounts of information to become short-term memory? | It can be chunked |
| What will happen if your temporal lobe is damaged? | You will live in the present and remote-past (Think 50 First Dates) |
| What can long-term memory involve? | Physical change in neuron shape |
| What bits of information does long-term memory usually store? | Important information such as address, how to get home, and all important numbers in life |
| What does the right cerebral hemisphere control? | Muscular activity and receives sensory input from the left half of the body |
| What does the left cerebral hemisphere do? | Controls input from the right half of the cerebrum |
| What separates the cerebrum into halves? | Longitudinal fissure |
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