ABIO2-Animal Physiology (PDF)

ABIO2-ANIMAL PHYSIOLOGY ROSE ANN Z. MASA ASSOCIATE PROFESSOR V COLLEGE OF ARTS AND SCIENCES Weight lifting can be used to develop muscle endurance as well as strength . Major muscle types of the body 1. Cardiac 2. Smooth 3. Skeletal Shape of muscles Answer the fo...

ABIO2-ANIMAL PHYSIOLOGY ROSE ANN Z. MASA ASSOCIATE PROFESSOR V COLLEGE OF ARTS AND SCIENCES Weight lifting can be used to develop muscle endurance as well as strength . Major muscle types of the body 1. Cardiac 2. Smooth 3. Skeletal Shape of muscles Answer the following : 1. Compare Isotonic from Isometric contractions (4pts) 2. Compare actin from myosin and how these filaments work( 5 pts) 3. Types of muscle with descriptions(6pts) 4. Discuss how muscle contraction occur(10 pts) Good luck☺☺☺ How to improve muscles?  You don’t have to be running for the muscular system to be at work. Even when you aren’t consciously moving, postural muscles keep you sitting or standing upright, respiratory muscles keep you breathing, the heart continuously pumps blood to all parts of your body, and blood vessels constrict or relax to direct blood to organs where it is needed. How to improve muscles?  A runner rounds the last corner of the track and sprints for the finish line. Her arms and legs are pumping as she tries to reach her maximum speed. Her heart is beating rapidly, and her breathing is rapid, deep, and regular. Blood is shunted away from her digestive organs, and a greater volume is delivered to her skeletal muscles to maximize their oxygen supply. These actions are accomplished by muscle tissue, the most abundant tissue of the body and one of the most adaptable. How to improve muscles?  In fact, movement within the body is accomplished in various ways:  by cilia or flagella on the surface of certain cells,  by the force of gravity, or  by the contraction of muscles.  But most of the body’s movement results from muscle contraction. Classification of Muscle Contractions In isometric (equal distance) contractions, the length of the muscle does not change, but the amount of tension increases during the contraction process. Isometric contractions are responsible for the constant length of the body’s postural muscles, such as the muscles of the back. In isotonic (equal tension) contractions, the amount of tension produced by the muscle is constant during contraction, but the length of the muscle decreases. Movements of the arms or fingers are predominantly isotonic contractions. Most muscle contractions are a combination of iso- metric and isotonic contractions in which the muscles shorten and the degree of tension increases. Concentric versus Eccentric Contractions Concentric contractions are isotonic contractions in which muscle tension increases as the muscle shortens. Many common movements are produced by concentric muscle contractions. Eccentric contractions are isotonic contractions in which tension is maintained in a muscle, but the opposing resistance causes the muscle to lengthen. Eccentric contractions are used when a person slowly lowers a heavy weight. Substantial force is produced in muscles during eccentric contractions, and muscles can be injured during repetitive eccentric contractions, as sometimes occurs in the hamstring muscles(skeletal) when a person runs downhill Muscle Tones The constant tension produced by body muscles over long periods of time. Muscle tone is responsible for keeping the back and legs straight, the head in an upright position, and the abdomen from bulging. Muscle tone depends on a small percentage of all the motor units in a muscle being stimulated at any point in time, causing their muscle fibers to contract tetanically and out of phase with one another. It also contributes to the control speed and amount of movement **postural-axial muscles(gravity is most important)- phasic-brief (gastro and urogenital system --contraction to high intensity ; rapid stretching of the tendon, attached muscle and muscle spindle Smooth muscle cells These are small and spindle-shaped, usually with one nucleus per cell. They contain less actin and myosin than do skeletal muscle cells, and the myofilaments are not organized into sarcomeres. As a result, smooth muscle cells are not striated. Smooth muscle cells contract more slowly than skeletal muscle cells when stimulated by neurotransmitters from the nervous system and do not develop an oxygen deficit. Contraction of Muscles The resting membrane potential of some smooth muscle cells fluctuates between slow depolarization and repolarization phases. As a result, smooth muscle cells can periodically and spontaneously generate action potentials that cause the smooth muscle cells to contract. The resulting periodic spontaneous contraction of smooth muscle is called autorhythmicity. Smooth muscle is under involuntary control, whereas skeletal muscle is under voluntary motor control. Some hormones, such as those that regulate the digestive system, can stimulate smooth muscle to contract. Smooth muscle Smooth muscle cells are organized to form layers. Most of those cells have gap junctions, specialized cell-to-cell contacts that allow action potentials to spread to all the smooth muscle cells in a tissue. Thus, all the smooth muscle cells tend to function as a unit and contract at the same time. Cardiac muscle Shares some characteristics with both smooth and skeletal muscle.Cardiac muscle cells are long, striated, and branching, with usually only one nucleus per cell. The actin and myosin myofilaments are organized into sarcomeres, but the distribution of myofilaments is not as uniform as in skeletal muscle. As a result, cardiac muscle cells are striated, but not as distinctly striated as skeletal muscle. When stimulated by neurotransmitters, the rate of cardiac muscle contraction is between those of smooth and skeletal muscle. Cardiac muscle Cardiac muscle contraction is autorhythmic. Cardiac muscle exhibits limited anaerobic respiration. Instead, it continues to contract at a level that can be sustained by aerobic respiration and consequently does not fatigue. Cardiac muscle cells are connected to one another by intercalated disks. Intercalated disks are specialized structures that include tight junctions and gap junctions and that facilitate action potential conduction between the cells. This cell- to-cell connection allows cardiac muscle cells to function as a unit. As a result, an action potential in one cardiac muscle cell can stimulate action potentials in adjacent cells, causing all to contract together. As with smooth muscle, cardiac muscle is under involuntary control and is influenced by hormones, such as epinephrine. TENDONS Most muscles extend from one bone to another and cross at least one joint. At each end, the muscle is connected to the bone by a tendon. Some broad, sheetlike tendons are called aponeuroses.A retinaculum( bracelet) is a band of connective tissue that holds down the tendons at each wrist and ankle. Muscle contraction causes most body movements by pulling one of the bones toward the other across the movable joint. Some muscles are not attached to bone at both ends. For example, some facial muscles attach to the skin, which moves as the muscles contract. ORIGIN AND INSERTION The two points of attachment of each muscle are its origin and insertion. The origin, also called the head, is the most stationary end of the muscle. The insertion is the end of the muscle attached to the bone undergoing the greatest movement. Origins are usually, but not always, proximal or medial to the insertion of a given muscle. The part of the muscle between the origin and the insertion is the belly.Some muscles have multiple origins; for example, the biceps brachii has two, and the triceps brachii has three. Muscle attachments Muscle Agonist versus Antagonist Muscles are typically grouped so that the action of one muscle or group of muscles is opposed by that of another muscle or group of muscles. For example, the biceps brachii flexes the elbow, and the triceps brachii extends the elbow. A muscle that accomplishes a certain movement, such as flexion, is called the agonist. A muscle acting in opposition to an agonist is called an antagonist. When flexing the elbow, the biceps brachii is the agonist, whereas the triceps brachii, which relaxes and stretches to allow the elbow to bend, is the antagonist. When extending the elbow, the muscles’ roles are reversed; the triceps brachii is the agonist, and the biceps brachii is the antagonist. Nomenclature of MUSCLES 1. Most muscles have descriptive names. 2. Some muscles are named according to their location, such as the pectoralis (chest) muscles. 3. Other muscles are named according to their origin and insertion, such as the brachioradialis (brachio, arm) muscle, which extends from the arm to the radius. 4. Some muscles are named according to the number of origins, such as the biceps (bi, two + ceps, head) brachii, which has two origins, and some according to their function, such as the flexor digitorum, which flexes the digits (fingers). 5. Other muscles are named according to their size (vastus, large), their shape (deltoid, triangular), or the orientation of their fasciculi (rectus, straight; 6. Recognizing the descriptive nature of muscle names makes learning those names much easier Following are the major functions of the muscular system: 1. Movement of the body. Contraction of skeletal muscles is responsible for the overall movements of the body, such as walking, running, and manipulating objects with the hands. 2. Maintenance of posture. Skeletal muscles constantly maintain tone, which keeps us sitting or standing erect. 3. Respiration. Muscles of the thorax carry out the movements necessary for respiration. 4. Production of body heat. When skeletal muscles contract, heat is given off as a by-product. This released heat is critical to the maintenance of body temperature.  Tongue and Swallowing Muscles 1. The tongue is very important in mastication and speech. 2. It moves food around in the mouth and, with the buccinator muscle, holds the food in place while the teeth grind the food. 3. The tongue pushes food up to the palate and back toward the pharynx to initiate swallowing. 4. The tongue consists of a mass of intrinsic muscles, which are located entirely within the tongue and change its shape. 5. The extrinsic muscles are located outside the tongue but are attached to and move the tongue 6. Swallowing involves a number of structures and their associated muscles, including the hyoid muscles, soft palate, pharynx (throat), and larynx (voice box). 7. The hyoid muscles are divided into a suprahyoid group (superior to the hyoid bone) and an infrahyoid group (inferior to the hyoid bone). 8. When the suprahyoid muscles hold the hyoid bone in place from above, the infrahyoid muscles can elevate the larynx. To observe this effect, place your hand on your larynx (Adam’s apple) and swallow 1. The muscles of the soft palate close the posterior opening to the nasal cavity during swallowing, preventing food and liquid from entering the nasal cavity. 2. When we swallow, muscles elevate the pharynx and larynx and then constrict the pharynx. 3. The pharyngeal elevators elevate the pharynx, and the pharyngeal constrictors constrict the pharynx from superior to inferior, forcing the food into the esophagus. 4. Pharyngeal muscles also open the auditory tube, which connects the middle ear to the pharynx. 5. Opening the auditory tube equalizes the pressure between the middle ear and the atmosphere. 6. This is why it is sometimes helpful to chew gum or swallow when ascending or descending a mountain in a car or changing altitude in an airplane. FACIAL MUSCLES FACIAL MUSCLES TONGUE AND SWALLOWING MUSCLES Learn to Predict 1-Muscular  Anthony decided to change his normal lifting routine to increase the number of repetitions (reps) of each weight. He was surprised when he became fatigued much more quickly than normal. in fact, his muscles became so weak that he could not continue exercising that particular muscle group. Using the knowledge you will gain about skeletal muscle contraction and answer the following questions. 1. Why did Anthony’s muscles fatigue when lifting the same weight as normal, but for more reps in a row? 2. What would be the Ca2+ level in the sarcoplasmic reticulum of his muscle after lifting many reps compared to lifting each weight once? BONES-TENDONS -MUSCLES 1. Part of a muscle attached by a tendon to a bone. 2. A muscle is composed of muscle fasciculi, each surrounded by perimysium. the fasciculi are composed of bundles of individual muscle fibers (muscle cells), each surrounded by endomysium. 3. The entire muscle is surrounded by a connective tissue sheath called epimysium, or muscular fascia. 4. Enlargement of one muscle fiber containing several myofibrils. 5. A myofibril extended out the end of the muscle fiber, showing the banding patterns of the sarcomeres. SACROMERE 1. A single sarcomere of a myofibril is composed mainly of actin myofilaments and myosin myofilaments. 2. The Z disks anchor the actin myofilaments, 3. the myosin myofilaments are held in place by the M line. 4. Part of an actin myofilament is enlarged. 5. Part of a myosin myofilament is enlarged.  Movement of the body. Contraction of skeletal muscles is responsible for the overall movements of the body, such as walking, running, and manipulating objects with the hands.  2. Maintenance of posture. Skeletal muscles constantly maintain tone, which keeps us sitting or standing erect.  3. Respiration. Muscles of the thorax carry out the movements necessary for respiration.  4. Production of body heat. When skeletal muscles contract, heat is given off as a by-product. This released heat is critical to the maintenance of body temperature. 5. Communication. Skeletal muscles are involved in all aspects of communication, including speaking, writing, typing, gesturing, and facial expressions. 6. Constriction of organs and vessels. The contraction of smooth muscle within the walls of internal organs and vessels causes those structures to constrict. This constriction can help propel and mix food and water in the digestive tract, propel secretions from organs, and regulate blood flow through vessels. 7. Contraction of the heart. The contraction of cardiac muscle causes the heart to beat, propelling blood to all parts of the body. Connective Tissue Coverings of Muscle  Each skeletal muscle is surrounded by a connective tissue sheath called the epimysium or muscular fascia.Each whole muscle is subdivided by a loose connective tissue called the perimysium into numerous visible bundles called muscle fasciculi Each fascicle is then subdivided by a loose connective tissue called the endomysium into separate muscle cells, called muscle fibers. Muscle Fiber Structure  Examining the structure of a muscle fiber helps us understand the mechanism of muscle contraction. A muscle fiber is a single cylindrical fiber, with several nuclei located at its periphery.  The largest human muscle fibers are up to 30 cm long and 0.15 mm in diameter. Such giant cells may contain several thousand nuclei. The cell membrane of the muscle fiber is called the sarcolemma ( flesh) The multiple nuclei of the muscle fiber are located just deep to the sarcolemma. Along the surface of the sarcolemma are many tubelike invaginations, called transverse tubules, or T tubules, which occur at regular intervals along the muscle fiber and extend inward into it.  T tubules are associated with a highly organized smooth endoplasmic reticulum called the sarcoplasmic reticulum. T tubules connect the sarcolemma to the sarcoplasmic reticulum. The sarcoplasmic reticulum has a relatively high concentration of Ca2+, which plays a major role in muscle contraction.  Inside each muscle fiber is the cytoplasm, called the sarcoplasm.It contains numerous myofibrils (, muscle), threadlike structures that extend from one end of the muscle fiber to the other.Myofibrils consist of two major kinds of protein fibers: actin myofilaments and myosin myofilaments.The actin and myosin myofilaments are arranged into highly ordered, repeating units called sarcomeres , which are joined end-to-end to form the myofibrils  Excitability of Muscle fibers Muscle fibers, like other cells of the body, have electrical properties. Most cells in the body have an electrical charge difference across their cell membranes. The inside of the membrane is negatively charged while the outside of the cell membrane is positively charged. In other words, the cell membrane is polarized. Resting membrane potential  The charge difference, called the resting membrane potential, occurs because there is an uneven distribution of ions across the cell membrane.  The resting membrane potential develops for three reasons:  (1) The concentration of K+ inside the cell membrane is higher than that outside the cell membrane;  (2) the concentration of Na+ outside the cell mem- brane is higher than that inside the cell membrane; and  (3) the cell membrane is more permeable to K+ than it is to Na+.  Recall the different types of ion channels:  non gated, or leak, channels, which are always open, and chemically gated channels,  which are closed until a chemical, such as a neurotransmitter, binds to them and stimulates them to open.  Because excitable cells have many K+ leak channels, K+ leaks out of the cell faster than Na+ leaks into the cell.  In other words, some K+ channels are open, whereas other ion channels, such as those for Na+, are closed.  In addition, negatively charged molecules, such as proteins, are in essence “trapped” inside the cell because the cell membrane is impermeable to them.  For these reasons, the inside of the cell membrane is more negatively charged than the outside of the cell membrane.  Skeletal muscle fibers do not contract unless they are stimulated by motor neurons.  Motor neurons are specialized nerve cells that stimulate muscles to contract. Motor neurons generate action potentials that travel to skeletal muscle fibers.  Axons of these neurons enter muscles and send out branches to several muscle fibers  Each branch forms a junction with a muscle fiber, called a neuromuscular junction.A more general term, synapse refers to the cell-to-cell junction between a nerve cell and either another nerve cell or an effector cell, such as in a muscle or a gland.  Neuromuscular junctions are located near the center of a muscle fiber.  A single motor neuron and all the skeletal muscle fibers it innervates constitute a motor unit.  A motor unit in a small , precisely controlled muscle, such as in the hand, may have only one or  Aftera 10-mile run with a sprint at the end, a runner continues to breathe heavily for a time. Indicate the type of respiration that is producing energy during the run, during the sprint, and after the run. Forearm muscles Anterior abdominal wall muscles Arm muscles Case on Point : Groin on Pull  Mr. X was playing soccer on a very cold October day.  He raced up to kick the ball, just as a player for the other team kicked the ball from the opposite direction.  Initially, the ball did not move. Lowe felt a sudden, sharp pain in the medial side of his right thigh and fell to the ground, holding the injured area. His coach and team trainer ran onto the field.  As the trainer pressed on the center part of his medial thigh, Mr. X felt severe pain.  He was able to stand and was helped off the field.  On the sideline, the trainer applied ice to the adductor region of Mr. X right thigh. For the next few days, was told to rest, along with icing the region, compressing the muscles, and elevating the thigh (RICE). He was also given anti- inflammatory drugs. Case on Point  After a couple days of rest, he began massage therapy.  He missed the next game but was able to play in the finals.  His injury was considered a grade 1 injury because there was pain and tenderness in the medial thigh muscles but no swelling.  Grade 2 injury, in which the muscle is partially torn, is more painful and results in swelling of the area.  Grade 3 injury, which involves a complete muscle tear, causes so much pain and swelling that the injured person cannot even walk.  A groin pull involves one or more of the adductor muscles, most commonly the adductor longus.  The damage usually occur in the musculotendon junction near the insertion. Goodenough J., et.al., (2014). Biology of humans: Concept, applications, and  issues. 5th Ed. Massachusetts: Pearson Education  Guyton, AC. & Hall JE. (2006). Textbook of Medical Physiology 11th Ed.  Pennsylvania: Elsevier Saunders.  Jabbar, A. (2017). Introduction to human physiology. Texas: Open Stax.  Masa, RZ (2022) LSPU Self-Paced Learning Module (SLM)in General Physiology  VanPutte, C. (2016). Seeley’s essentials of anatomy physiology. Academia.  https://www.academia.edu/29647351/Seeleys_Essentials_of_Anatomy_  Physiology_Van_Putte_Cinnamon_SRG?auto=download