Chapter One: Structure and Function of Body Systems Flashcards
Axial Skeleton
Consists of the:
- Skull
- Vertebral Column
- Ribs
- Sternum
Appendicular Skeleton
Consists of the:
- Shoulder+Scapula
- Bones of the upper extremities
- Pelvic Girdle
- Bones of the lower extremities
Joints: Fibrous
- Allow little to no movement
Example: Sutures of the skull
Joints: Cartilaginous Joints
- Allow limited movement
Example: Vertebral bodies and discs
Joints: Synovial Joints
- Allow a wide range of movements depending on the joint
- Most joints in the body
- Bone ends have smooth hyaline cartilage and joint is enclosed in a capsule with synovial fluid.
Joints: Uniaxial
- One plane of movement
Example: Elbow
Joints: Biaxial
- Two planes of movement
Example: Ankle
Joints: Multiaxial
- Multiple planes of movement
Example: Shoulder
Vertebral Column
- Cervical: 7
- Thoracic: 12
- Lumbar: 5
- Sacrum: 5 fused
- Coccyx: Fused at end of pelvis
Muscle Fiber Macrostructure: Epimysium
- Covers an entire skeletal muscle
- Contiguous with the tendon
Muscle Fiber Macrostructure: Periosteum
- Specialized connective tissue covering bones that tendons attach to
Muscle Fiber Macrostructure: Muscle Fibers
- Cells of the skeletal muscle
- Have several nuclei situated along the length of the muscle fiber
Muscle Fiber Macrostructure: Fasiculi
- Groupings of up to 150 muscle fibers
- Beneath the epimysium
Muscle Fiber Macrostructure: Perimysium
- Specialized connective tissue that surrounds a fasciculi.
Muscle Fiber Macrostructure: Endomysium
- Specialized connective tissue that surrounds a muscle fiber
Muscle Fiber Macrostructure: Sarcolemma
- Muscle fiber membrane
- Contiguous with the endomysium
Neuromuscular: Junction or Motor End Plate
- Junction between the motor neuron and muscle it innervates
- Each muscle fiber has only one neuromuscular junction/motor end plate but one motor neuron can innervate several muscle fibers.
Neuromuscular: Motor Unit
- A motor neuron and all the muscle fibers it innervates
- All the muscles fibers of a motor unit contract together when they are stimulated by the motor neuron
Muscle Fiber Microstructure: Sarcoplasm
- Cytoplasm of the cell
- Contains most cellular organelles for the muscle fibers
Muscle Fiber Microstructure: Myofibrils
- Several within the sarcoplasm
- Contain the contractile unit of muscle
Muscle Fiber Microstructure: Myofilaments: Mysoin
- Consist of a Globular head, hinge point and a fibrous tail.
- Globular head protrude away from the myosin filament at regular intervals.
- A pair of myosin filaments forms a cross bridge
Muscle Fiber Microstructure: Myofilaments: Actin
- Two strands arranged in double helix
Muscle Fiber Microstructure: Sarcomere
- Smallest contractile unit of a muscle
- Actin and myosin filaments organized longitudinally
Muscle Fiber Microstructure: M Bridge
- Site of anchoring for adjacent myosin filaments
- Center of a sarcomere
- Center of the H zone
Muscle Fiber Microstructure: Z-line
- Sight of anchoring of actin filaments
- In the middle of the I-band
- Longitudinal band through the I-Band
Muscle Fiber Microstructure: A-band
- Alignment of myosin filaments
Muscle Fiber Microstructure: I-Band
- Area of two adjacent sarcomeres that contain only actin
- Decreases in size during contraction
Muscle Fiber Microstructure: H-Zone
- Area in the center of a sarcomere where only the myosin filaments are present
- Decreases in size during contraction
Muscle Fiber Microstructure: Sarcoplasmic Reticulum
- Intricate system of tubules parallel to and surrounding each myofibril
- Terminates as vesiciles in the vicinity of the Z-lines
- Calcium ions stored in the vesicles
Muscle Fiber Microstructure: T-tubules
- Perpendicular to the sarcoplasmic reticulum and terminate in the vicinity of the Z-line between two vesicles.
Action Potential
- Discharge of a nerve impulse that causes muscular contraction
Sliding Filament Theory
- The action of myosin cross bridges pulling on the actin filaments and causing them to slide inward pulling the Z-lines toward the center of the sarcomere and shortening the muscle fiber and causing shrinking of the H-zone and I-band
Sliding Filament Theory: Resting Phase
- Little calcium present in the myofibril
- Most of the calcium is stored in the sarcoplasmic reticulum
- Very few myosin cross bridges are bound to actin
Sliding Filament Theory: Excitation Phase
- Sarcoplasmic reticulum is stimulated to release calcium which binds to troponin.
- Binding of calcium to troponin causes shift in tropomyosin which is along the length of the actin filament in the groove of the double helix
- Myosin cross bridge attaches more rapidly to actin
Sliding Filament Theory: Troponin and Tropomyosin
- Proteins situated along actin molecules that allow for myosin cross bridge attachment to actin contributing to muscular contraction
Sliding Filament Theory: Force production
- The amount of force produced by a muscle at any instant is directly related to the number of myosin cross bridges bound to actin filaments cross sectionally at that instant
Sliding Filament Theory: Contraction Phase
- Contraction driven by hydrolysis of an ATP to ADP and phosphate catalyzed by Adenosine triphosphatase (ATPase).
Sliding Filament Theory: Recharge Phase
- Phase when ATP is uncoupling the myosin cross bridge from actin to allow for another re-coupling
- Several repeated cycles must be repeated to cause muscular contraction
Sliding Filament Theory: Relaxation Phase
- Stimulation of a motor nerve stops
- Calcium pumped back into the sarcoplasmic reticulum
- Actin and myosin are back to their unbound state
Neuromuscular: Acetylcholine
- Neurotransmitter released which diffuses across the neuromuscular junction causing excitation of the sarcolemma
- Once a sufficient amount is released an action potential is generated and the muscle fiber contracts
Neuromuscular: All or None principle
- A motor unit is not capable of selectively contracting one muscle fiber it innervates. If it generates an action potential all the fibers it innervates must contract simultaneously.
Neuromuscular: Twitch
- One contraction of a muscle fiber
Neuromuscular: Tetanus
- Summation of several rapid twitches of a muscle fiber that fuse
- The maximal amount of force a muscle can produce.
Muscle Fiber Types: Type I
- Slow twitch
- Efficient and fatigue resistant
- High capacity for aerobic energy
- High oxidative capacity
- Limited potential for rapid force development
Muscle Fiber Types: Type IIa and Type IIx
- Fast twitch
- Inefficient and fatiguable
- Low capacity for aerobic energy
- Low oxidative capacity
- High anaerobic power
- Rapid force development
- Type IIa have greater capacity for aerobic metabolism than type IIx
Motor Unit Recruitment Patterns
- Motor units that innervate type I, type IIa and type IIx are activated in accordance with the activity.
- Type I muscles and motor units for longer duration low power events
- Type IIa and type IIx for shorter duration and explosive movements
Proprioception: Proprioceptors
- Specialized sensory receptors located within joints, muscles, and tendons
- Relay information concerning muscle dynamics to the central nervous system
- Maintain muscle tone and perform complex coordinated movements.
Proprioception: Muscle Spindles
- Proprioceptive organs that consist of several modified muscle fibers enclosed in a sheath of connective tissue
- Considered intrafusal fibers or fibers that run parallel to the normal muscle fibers or extrafusal fibers.
- Provide information related to muscle length and rate of change of length
Proprioception: Muscle Spindles: Activation/process
- Muscle stretch activates the sensory neurons of the muscle spindles.
- This sends an impulse to the central nervous system at the spinal cord.
- This results in the activation of the motor neurons that innervate the same muscle.
Proprioception: Muscle Spindles: Load increases and fine motor control
- As load increases the muscle is stretched to a greater extent causing increased activation of the muscle spindle causing increased activation of the muscle
- Muscles that perform fine movements have increased muscle spindles per unit of mass to help ensure exact control of contractile activity.
Proprioception: Golgi Tendon Organ
- Proprioceptive organs located in tendons near the myotendinous junction in a series (attached end to end) with extrafusal muscle fibers
- Activated when the tendon the Golgi tendon organs are attached to is stretched
- As muscle tension increases Golgi tendon organ discharge increases
Proprioception: Golgi Tendon Organ: Activation/procress
- GTO synapses with an inhibitory interneuron in the central nervous system at the spinal cord which in turn synapses with and inhibits a motor neuron for the same muscle.
- Results in a reduction of tension within the muscle and tendon
- Protects against excessive tension development
Blue Box: Methods for Athletes to improve force production
- Incorporate phases with heavy loads for improved neural recruitment
- Increase cross sectional area of muscles involved in the desired activity
- Perform multi-muscle, multi-joint exercises that can be done with more explosive actions to optimize fast twitch muscle recruitment.
Cardiovascular System: Heart
- Four chambers
- Two atria and two ventricles
- Right atria provides blood to right ventricle. Left atria provides blood to left ventricle
- Right ventricle pumps blood to the lungs
- Left ventricle pumps blood systemically
Cardiovascular System: Valves
- Tricuspid valve and mitral valve (bicuspid) collectively called the atrioventricular valves and prevent the back flow of blood from the ventricles into the atria during ventricular contraction (systole)
- Aortic and pulmonary valves collectively called the semilunar valves prevent back flow of blood from the aorta and pulmonary valve into the ventricles during ventricular relaxation (diastole)
- Each valve opens and closes passively with backward pressure gradient pushes blood back against it.
Cardiovascular System: Conduction System: Sinoatrial Node
- SA Node: Where rhythmic electrical impulses are normally initiated
- Activate atria first
Cardiovascular System: Conduction System: Atrioventricular Node
- AV Node: Where the impulse is delayed slightly before passing into the ventricles
Cardiovascular System: Conduction System: Atrioventricular Bundle
- Conducts the impulse to the ventricles
Cardiovascular System: Conduction System: Bundle Branches
- Conduct impulses to all parts of the ventricles via the Purkinje fibers
Cardiovascular System: Conduction System: Heart Rate
- Normal: 60-100
- Bradycardia: Below 60 bpm
- Tachycardia: Over 100 bpm
Cardiovascular System: Electrocardiogram Waves
- P wave
- QRS complex
- T wave
Cardiovascular System: Electrocardiogram Waves: P wave and QRS complex
- Recordings of electrical depolarization that causes mechanical contraction
Cardiovascular System: Electrocardiogram Waves: Depolarization
- The process where by the membrane electrical potential is reversed causing the normally negative potential inside the membrane becomes slightly positive and the outside becomes slightly negative
Cardiovascular System: Electrocardiogram Waves: P Wave is
- Atrial depolarization and contraction
Cardiovascular System: Electrocardiogram Waves: QRS complex is
- Ventricular depolarization and contraction
Cardiovascular System: Electrocardiogram Waves: T wave is
- Ventricular repolarization and relaxation
Cardiovascular System: Blood Vessels: Arterial vs Venous
- Artierial: Carry blood away from the heart to the body
- Venous: Carry blood from the body to the heart
Cardiovascular System: Blood Vessels: Arteries
- Transport blood to the body
- Strong muscular walls to manage high pressures of blood pumped from the heart
- Transport blood to arterioles
Cardiovascular System: Blood Vessels: Arterioles
- Act as control vessels regulating blood flow to capillaries
- Strong muscular walls to manage high pressures of blood pumped from the heart
- Capable of closing completely or dilating to many times their size
- Primary blood flow regulator in response to demand
- Transport blood to capillaries
Cardiovascular System: Blood Vessels: Capillaries
- Regulate the exchange of oxygen, nutrients, electrolytes, hormones and other substances between the interstitial fluid and blood
- Relatively thin permeable walls
Cardiovascular System: Blood Vessels: Venules
- Venous version of arterioles
- Collect blood at the other end of capillaries
- Converge into veins
Cardiovascular System: Blood Vessels: Veins
- Transport blood back to the heart
- Venous walls are thin due to low pressure
- Antigravity veins have valves to regulate back flow of blood as it is transported back to the heart
Cardiovascular System: Blood
- Carries oxygen to tissues
- Carries carbon-dioxide to be removed from the body
Cardiovascular System: Blood: Hemoglobin
- Iron protein molecule carried by red blood cells
- Transports oxygen
- Acts as an acid base buffer by regulating hydrogen ion concentration
Respiratory System: Trachea
- Largest passage for inspired oxygen
- First portion of respiratory passage
Respiratory System: Bronchi
- Right and Left portion to right and left lungs
Respiratory System: Bronchioles
- All divisions after the right and left bronchi
- Transport air to the alveoli
Respiratory System: Exchange of air
- Lung oxygen exchange is driven via two mechanisms diaphragmatic movement and chest wall expansion via rib movement
- Resting inspiration and expiration is driven almost exclusively via the diaphragm
- Chest wall expansion via rib movement upward is driven via muscles of inspiration
- Chest wall decompression via rib movement downward is driven by muscles of expiration
Respiratory System: Pleural pressure
- Pressure of the space between the parietal pleura and and visceral pleura
- Slightly negative
- helps to drive inspiration
Respiratory System: Alveolar pressure
- Pressure inside the alveoli when the glottis is open and no air is flowing into or out of the lungs
- Pressure is equal to atmospheric pressure
- To cause inward flow of air the pressure in the alveoli must fall below atmospheric pressure
- To cause outward flow of air the pressure in the alveoli must increase above atmospheric pressure
Respiratory System: Exchange of Respiratory Gasses: Diffusion
- Oxygen diffuses from alveoli into pulmonary blood
- Carbon dioxide diffuses from pulmonary blood into alveoli
- Other molecules diffuse via kinetic motion of the molecules themselves
- Diffusion of gases is driven from high concentration to low concentration and is dependent on the partial pressure of each gas
Respiratory System: Exchange of Respiratory Gasses: Partial pressure of gasses
- Partial pressure of Oxygen in the alveoli at rest is 60mmHg greater than that in pulmonary capillaries causing oxygen to diffuse from alveoli into the pulmonary capillaries
