exam 2 Flashcards
What are the three categories of muscle, based on microscopic appearance? What sets them apart from one another?
Skeletal:multinucleate with striations (voluntary, bones and cartilage), Cardiac: only occurs in the heart (involuntary, cells are branching, intercalated disks), Smooth: lack striations (involuntary, devoted to visceral functions such as digestive tract blood vessels and lungs)
How are muscle cells organized to form a muscle?
Each muscle cell is encased in a sarcolema which inside are myofibrils made up of myofilaments. Myofibrils consist of chains of repeating sarcomeres, which include thick and thin myofilaments. Myofilaments are made of actin (thin, dark straitions) and myosin (thick, light striations) proteins and anchored to Z disks
How do muscles contract?
Skeletal muscle and cardiac muscles contract by nerves stimulating muscle to contract with generates tensile forces, electrical impulses travel by way of calcium ion channels in cell membrane, sliding of thick and thin filaments overlap to shorten muscles
Smooth muscles: acin and mysoin filaments are much fewer, calcium ions come from extracellular fluid nearby, thick filaments pull on thin ones which pull on network of dense bodies (force is transferred to plasma membrance and the entire cell shortens), slower contractions but can remain contracted a longer time, less resistant to fatigue because actin and myosin filaments do not detach right away- uses less ATP than skeletal muscle
How does the tendon act in an elastic way to store energy?
Energy is stored within a muscle and tendon, stretching like a rubber band and releasing during repetitive events. Ex) in running 33% of energy is recycled per each stride
extensors vs flexors
Bending and straightening
Flexors: bend one body part relative to another about a joint
Extensors: straighten a part of the body
Ex) elbows towards/away from biceps
adductors vs abductors
In and out
Adduction: draw limb towards ex) lower arm from T-pose
Abduction: move limb away from midline ex) raise arm to T-pose
levators vs depressors
Levators and depressors are a special kind of abduction/adduction
Levators: close jaws
Depressors: open jaws
protractors vs retractors
Projecting away and back
Protractor: project a part out ex) moving shoulder forward
Retractor: bringing a part back ex)pulling shoulder backward
supinators vs pronators
Rotating
Supinators: rotate palm or sole up
Protonators: roate palm or sole down
Sphincters
Opening and closing
Sphincters: close tubes, circular muscles ex)pupil
Dialators: open tubes
What are the myomere shapes and trends in axial muscle evolution across fishes? What about axial muscle trends in tetrapods?
There is a trend from cephalochordates and jawless fishes going to gnathostomes that there are increasingly complex myomeres and myosepta. V-shaped muscle bocks become W shaped in gnathostomes which helps distribute muscle forces and myosepta act as little tendons that direct forces to specific muscle fibers. Axial muscles are reduced in tetrapods since appendicular muscles are doing more work. Axial muscles also become specialized; exert more control over vertebral column flexion, rib cage movement. In salamanders epaxial muscles are on segmented muscle and hypaxial muscles divided into 3 layers. In lizards epaxial muscles differentiated and reduced, hypaxial muscle form body wall, horizontal septum lost. In birds axial muscles are reduced due to fusion in vertebral column. In mammals additional subdivisions, hypaxial muscles become recus abdominis which supports ventral body wall.
What are some muscular adaptations for running?
Bunching of appendicular muscles proximally in limb, reduces mass carried by limb, most extreme examples in perissodactyls (horses) and artiodactyls (deer) also seen in bipedal archosaur
What muscular adaptations are seen in flying birds?
Axial muscles diminished, appendicular muscles expanded. Also keep muscle mas close to body, pectoralis muscles become huge (to depress wings) supracoracoideus now inserts on coracoid through tendon to lift wing, long tendons give precision, patagialis keeps wing shape aerodynamic.
What is the difference between intrinsic and extrinsic eye muscles?
Intrinsic: muscles that move or shape the lens to focus light on the retina
Extrinsic: rotate eyeball within the orbit to direct the eye’s gaze
What are some novel functions that muscles have evolved to do, aside from contracting?
Sound producing, drumming muscles on swim bladder, bird syrinx is a muscular organ at split of trachea and lungs that allows birds to sing continuously on in and out breath, electrically producing muscels that depolarize using sodium and potassium ions.
Epimesium
muscle tissue membrane around the entire muscle organ
Perimysium
muscle tissue membrane around groups of cells
Endomysium
muscle tissue membrane around a single fiber/cell
Sarcolema
cell membrane that encases each muscle cell
Intercalated discs
in cardiac muscles intercalated discs join togehter short cells. specialized junctions between cardiac muscle fibers (cardiomyocytes) that allow for rapid electric transmission, called an action potential, and nutrient exchange.
desmosomes
anchors intercalated disks, consist of protein plaques with root-like fibers
fascia adherens
span space in between muscle cells
gap junctions
how electrical impulses are sent between two muscle cells, small pores in between each cell
aponeuroses
thin, flat, and tough sheets of muscle tendons, ex) abdominal
fascia
sheets of fibrous connective tissue that wrap and bind muscles together (tendons) ex) fingers have tendons conneting them to arms
multiunit smooth muscle
motor units come from autonomic nervous system and synapse with individual cells, seen in large arteries, airways, iris, and arrector muscles
single unit smooth muscle
cells are connected to eachother by gap junctions (much fewer neurons), inner circular layer and outer longitudinal layer, found in most blood vessels, digestive, respiratory, urinary, and reproductive tracts
tonic muscles
slow contracting and produce little force, but can sustain contraction for a long time, used for postural support, coomon in axial and appendicular muscles, common in amphibians and reptiles (not seen in humans/mammals)
Twitch
Twitch (phasic) fast contraction, used for rapid movements, found commonly in all vertebrates
Slow twitch: take longer to reach maximum force, more resistant to fatigue
Fast twitch: thick and strong fibers adapted for quick responses, not fatigue resistant
Morphological vs physiological cross section
Morphological cross section: ara of a muscle perpendicular to it’s longitudinal axis at the widest part
Physiological cross section: area of all muscle fibers perpendicular to thier longitudinal axis
Morphological and physiological are same if muscle fibers run parallel, different if they run obliquely
Muscle origin vs insertion
Origin: (relatively fixed point of attachement, site of origin is the head, where muscle anchors to
Insertion: mobile point of attachment, site of insertion is the slip, origin stays still and insertion moves AKA slips during muscle contraction
epaxial muscles
part of axial musculature, used for locomotion, dorsal
hypaxial muscle
part of axial musculature, used for locomotion, ventral
horizontal septum
part of axial musculature, used for locomotion, absent in cyclostomes
myomeres
muscle blocks
myosepta
connective tissue separating muscles
hypobranchial muscles
ventral, below jaws and gill arches, contriubutes to tongue
branchiomeric muscles
sides of gill arches, each arch has its own dorsal and ventral superficial constricors, interarcuals (dorsal and lateral), adductor, and interbranchial (between gill rays) began as a water pump, modified for jaws/feeding
What is unidirectional vs bidirectional respiration?
What is unidirectional vs bidirectional respiration?
Which taxa have external gills? Why do they have them?
External gills are filamentous capillary beds that protrude into surrounding water, seen in many vertebrate larvae and some adults (lungfish, amphibians, some actinopterygians, chondrichthyans) water currents flow across their surface to aid in exchange (passive!)
What are some cutaneous respiratory organs? How do they work? Which vertebrate groups do cutaneous respiration?
Cutaneos respiratory organs are where skin supplement breathing, seen in fish amphibians and reptiles, plood circulates near surface of the skin and establishes countercurrent exchange system, often accompanied by increases in surface area (skin folds)
Dual pump
Buccal and opercular cavities expand, while operculum is closed (water drawn in through mouth), mout closes and buccal and opercular cavities are compressed (water pushed out trhough operculum)
Buccal pump (two- vs four-stroke)
Two stroke: Bidirectional and in tetrapods, expansion of buccal cavity mixes old air from the lungs with fresh air in the mouth, upon compression the mixed air is forced into lungs and excess air is expelled through the nares
Four stroke tetrapods (amphibians):1) buccal cavity expands to draw fresh air in through open nares 2) the glottis opens rapidly, relaeasing spent air from the elastic lungs through the open nares 3) the nares close and the floor of the buccal cavity rises, forcing the fresh air held in this cavity into the lungs through the open glottis 4) the glottis closes retaining the air that has just filled the lungs and nares open agian
Aspiration pump
amniotes and birds, air is sucked in by low pressure created in lungs (lungs located within pump) pump includes rib cage and muscular diaphragm, mouth no longer involved (feeding and ventilation are decoupled) useful for mammals who do a lot of chewing
How do lampreys and hagfish ventilate their gills?
In lampreys oral disk is suctioned onto surface, so water flows both in and out of pharyngeal pores, muscle compression in pharynx drives ventilation
In hagfish adults scroll and unscoll velum and contract branchial pouches to produce a unidirectional water current
How are snake lungs specialized for breathing during feeding?
Asymmertrical paired lungs in many snakes (left smaller) left lung lost entirely in some. When swallowing prey snakes compress saccular (posterior) portion to continue ventilation.
How are bird lungs organized? How do they route air across their parabronchi?
Two lungs connected to a trachea and ventilated by an aspiration pump, the trachea splits into two primary bronchi that do not enter the lung but extended to the posterior air sacs, nine avascular air sacs are connection to the lungs and extend into the cores of most large bones, instead of blind-ended alveoli they have one-way parabronchi that permit air to flow through the lungs, small air capillaries open off the walls of each parabronchus and gas exchange with the blood occurs in the air capillaries. During exhalation 2 air from posterior air sacs moves to parabronchi and faveoli, plus air in anterior air sacs flow out through bronchi.
How do fish regulate the amount of water that flows over their gills? Why do they do this?
Rather than breathin in and out through the mouth, fish use a one-way system, passing water in one direction over their gills. Water goies in the mouth, acoss the gills, and out through the opercula (the bony covering protecting their gills). A large amount of water needed to pass over the gills to get enough oxygen out of the environment
branchial arches
series of bony loops present in fish which support the gills, all vertebrate embryos develop pharyngeal arches as an evolutionary byproduct, start with 6
branchial rays
fine cartilaginous rods that articulate at their bases with the branchial arch
primary lamellae
part of internal gills, branchial arches support gill filaments, support secondary lamellae
secondary lamellae
part of internal gills, contain capillary beds
countercurrent exchange
blood in secondary lemellae flows in one direction and water flows in the opposite direction
faveoli
internal compartments that open into the central chamber and contain capillaries in the lung, internal subdivisions of the lung wall that open to a common central chamber found in amphibians and reptile lungs
bronchi
mammals, within lungs, two bronchi (each lobe of the lung)
Bronchioles
smaller branches off of the bronchi in the lungs
trachea
where lungs are connected to the environment, glottis forms the entrance
surfactant
reduces surface tension at air-water interface, alveoli are covered by mucus, need help to break tension so they can inflate
ram ventilation
fish swims forward with its mouth open taking in water that passes over the gills. The drawback to ram ventilation is that the fish has to swim continuously to be abble to continue breathing, occurs in active fishes swimming through the water
holobranch
arch with lamellae on anterior and posterior sides
hemibranch
arch with lamellae only on one side
phsostomus swim bladder
connected to the pharynx through the pneumatic duct, air volume controlled by fish swallowing air and pushing it through pneumatic duct
Physoclsitorous swim bladder
not connected to the digestive tract so that fish with these swim bladders must diffuse gas from the blood to fill and collapse them.
limiting membrane
in turtles, connects to the abdominal muscles that contract or relax, allows lungs to open/close by acting as alternative to aspiration pump because of shell
parabronchi
in bird lungs, an alternative to blind-ended alveoli, parabronchi permit air flow through the lungs
air capillaries
in bird lungs, small air capillaries open off the walls of each parabronchus, and gas exchange with the blood occurs in the air capillaries
ventilation
rate of fluid passing over respiratory surface
perfusion
rate of blood moving through respiratory organ
How do arterioles route blood to or from a capillary bed?
Most capillaries drain into venule or end of metarteriole (most goes back to heart) most control involves constriction of upstream arterioles. Arterioles connect with even smaller blood vessels called capillaries. Through the thin walls of the capillaries, oxygen and nutrients pass from blood into tissues and waste products pass from tissues into blood.
How do pressure gradients contribute to blood flow through the vessels? What happens to pressure as blood flows away from the heart?
Pressure gradient determines the flow of blood back to the heart depends upon pressure in the veins is much lower than in arteries, drives blood back into the heart. As blood moves from the venules to veins the average blood pressure drops, but the blood velocity increases, this pressure gradient drives blood back towards the heart.
How does resistance affect blood flow?
Resistance is the force that opposes the flow of a fluid. In blood vessels, most of the resistance is due to vessel diameter (vasoconstriction and vasodilation) as vessel diameter decreases the resistance increases and blood flow decreases, increasing resistance decreases blood flow
What are the similarities and differences between blood vessels/flow and lymphatic vessels/flow?
Blood has RBCs, WBC’s, platelets, and a fluid called plasma. Whereas lymph has WBC’s and watery fluid. They both have immune and also circulatory functions in them. One of the major differences between them is that blood flows through blood vessels and lymph through lymphatic vessels
What are the major locations of collections of lymph nodes?
Cervical lymph nodes (head and neck), axillary lymph nodes (armpit, upper limb and female breast), thoracic (mediastinum, lungs, and airway), abdominal (urinary and reproductive), intestinal and mesenteric (mesenteris, digestive tract) inguinal (groin, entire lower limb), popliteal (back of knee, foot and leg)
How has the ancestral pattern of six aortic arches been modified in each major vertebrate group?
Basic 6-arch pattern at the base of jawed vertebrates
Cyclostomes: 8+ aortic arches
Chondrichthyans: have all 6 (first two/spiracular are highly modified and have few gill lamellae
Teleosts have 4 (first 2 lost/modified)
Lungfish have 5 (2-6) only arches 2,5,6 have gill lamellae, oxygenated blood from lungs goes to arches 3 &4 and directly to body, deoxygenated blood from veins goes through arches 5 & 6 and then to lung
Amphibians have 4 (3-6)
Squamates/turtles have 3 (3,4,6)
Birds have 3 (3,4,6) systemic arch goes to right
Mammals have 3 (3,4,6) systemic arch goes to left
How does the hepatic portal system work?
Hepatic portal vein receives blood specifically from the stomach, instestines, pancrease, and spleen and carries it into the liver through the porta hepatis. The porta hepatis serves as the point of entry for the hepatic portal vein and proper hepatic artery and is the point of exit for the bile passages
How is the heart organized in major vertebrate groups – how many chambers and any unique features?
*cyclostomes, chondrichthyans, and Teleosts have 1 atrium, 1 ventricle
Cyclostomes: Hafish and lamprey
Hagfish: branchial heart with sinus venosus, atrium, ventricle, vena cava (no bulbus/conus arteriosus) lots of simple accessory “hearts”- portal, caudal, cardinal
Lamprey: sinus venosus,atrium, ventricle, bulbus arteriosus (expands and absorbs P changes generated by ventricle)
Chondrichthyans: sius venosus, atrium, ventricle, conus arteriosus (muscular), special conal valves prevent backflow of blood
Teleosts: sinus venosus, atrium, ventricle, bulbus arteriosus (not muscular), bulbus arteriosus helps to absorb large increases in blood pressure (depulsation)
Lungfish: (2 chambers, walls partially separate) Partially divided atria and ventricles: interatrial septum, atrioventricular plug, interventricular septum, when lungfish breathe air left channel receives oxygenated blood from lungs, right channel carries deoxygenated systemic blood, spiral valve in conus arteriosus helps keep blood separate
Amphibians: 3 chambers, complete interatrial septum, one ventricle, conus arteriosus with spiral valve to separate blood streams
Reptiles: 3 chambers, 2 atria, 1 ventricle, 3 sub chambers in ventricle (cavum venosum, cavum pulmonale, cavum arteriosum)
Crocodilians: 4 chambers (2 atria, 2 ventricles), in crocodilians the foramen of panizza normally connects the two sides of the systemic circuit, birds, mammals: 4 chambers (2 atria, 2 ventricles)
How do crocodilians use a cardiac shunt when diving?
they do a cardiac shunt when diving and holding their breath- they constrict blood vessels and use special valves to route blood away from the pulmonary trunk
in crocodiles, shunts blood away from lungs when diving, vasoconstriction in lungs obstructs pulmonary circulation- cog tooth valves close trunk, pressure higher in R ventricle=deoxygenated blood exits mostly through systemic arch (recycle systemic blood and monitor pH in dive
plasma matrix
fluid portion of blood, mostly water + protein + nutrients
erythrocytes
red blood cells, used in gas exchange
leukocytes
white blood cells, used in immune system regulation
platelets
component of blood that are not true cells, involved in clotting
arteries
carry blood away from heart, usually oxygen rich, red
veins
carry blood back to heart, usually oxygen poor, blue
capillaries
connect smallest arteries to smallest veins to create a circuit
tunica interna
endothelium, lines the blood vessel and is exposed to blood, secretes chemicals that stimulate dilation or constriction, normally repels blood cells and platelets to prevent clotting
tuninica media
middle layer, contains smooth muscle, collage, elastic, contracts vessels
tunica esterna
outer layer, consists of loose connective tissue, anchors vessels in place (vessel wall)
arterioles
control the amount of blood flowing to organs through capillaries (smallest arteries are capillaries, arterioles are slightly larger)
metarterioles
throughfare channels that link arterioles to directly to venules (bypass capillary bed)
precapillary sphincters
control flow in capillary beds supplied with metarterioles, when sphincters are relaxed capillaries have more blood, when sphincters contract they constrict the entry to the capillary and blood bypasses the capillary