Human Cardiovascular System Overview

Human Cardiovascular System

• Human cardiovascular system is a dual system
• Left side: systemic circuit
• Right side: pulmonary circuit

Blood Flow

• Blood flows from superior and inferior vena cava
• To the right atrium
• Through the tricuspid valve
• To the right ventricle
• Through the pulmonary valve
• To the pulmonary arteries
• To the pulmonary veins
• To the left atrium
• Through the mitral valve
• To the left ventricle
• Through the aortic valve
• Finally into the aorta

Conduction System of the Heart

• Structure: Sinoatrial (SA) node, Atrioventricular (AV) node, Atrioventricular Bundle(s), Purkinje Fibers
• Function: SA node initiates heart electrical activation (pacemaker), AV node delays electrical activation allowing ventricles to fill, and Purkinje fibers facilitate ventricle contraction from bottom to top
• Pacemaker of the heart, which causes ~100ms delay allowing ventricles to fill with blood

Cardiac Output

• Cardiac output is a measurement of the amount of blood pumped by each ventricle in one minute.
• Calculating Cardiac output: Stroke Volume × Heart Rate

Major Factors Influencing Cardiac Output

• Factors influencing stroke volume include heart size, fitness level, gender, contractility, duration of contraction, preload (EDV), and afterload (resistance).
• Factors influencing heart rate include autonomic innervation, hormones, fitness level, and age.

Respiratory System

• The conducting zone is responsible for transporting air to the respiratory zone.
• The pharynx has three regions: nasopharynx, oropharynx, and laryngopharynx
• The conducting zone includes the pharynx and tube that continues into the nasal cavities.
• The respiratory zone is where gas exchange occurs.
• Alveoli are grape-like sacs, which are attached to the alveolar ducts.

Biomechanics Principles

• Biomechanics applies mechanical principles to living systems.
• Mechanics studies the interaction between objects.
• Position: linear and 3D, orientation-angular and 3D
• Newton's Laws: first law states objects remain at rest or constant motion unless a force acts, second law states the change in motion is proportional to the force and third law states for every action there’s an equal opposite reaction

Definition of Force and Torque

• Force causes an object to change velocity
• Torque causes an object to rotate (force x moment arm).

Lever Systems

• First-class levers: effort and load on opposite sides of the joint, examples include neck flexion/extension.
• Second-class levers: effort and load on the same side of the joint, examples include ankle plantarflexion/dorsiflexion.
• Third-class levers: effort and load on the same side of the joint, effort force has a smaller moment arm, example includes elbow flexion.

Forces Related to Human Movement

• Internal forces are the effort (muscle tension, pressure, tendon/ligament tension).
• External forces are resistance (gravitational force, friction etc).

Injury Classifications

• Acute injuries result from a single force exceeding tissue tolerance
• Chronic injuries result from sustained low-force exposures over time, degrading tissue tolerance

Control of Human Movement

• Classifications: exteroceptors, interoceptors, proprioceptors, chemoreceptors, osmoreceptors
• Exteroceptors receive external stimuli like vision, hearing, smell, and taste.
• Interoceptors receive internal stimuli like hunger, pain, and pressure
• Proprioceptors give information about body position and movement
• Chemoreceptors detect chemical changes, (e.g. taste, smell)
• Osmoreceptors detect changes in solute concentration

Mechanoreceptors

• These receptors respond to physical stimuli (e.g. touch, pressure, vibration, and temperature).

Table of Mechanoreceptors

• The table includes receptors names (e.g. Free Nerve Endings, Merkel's Discs, Ruffini's Corpuscle), their locations (e.g. skin), and stimuli they respond to (e.g. pain, vibration).

Primary Motor Cortex and Motor Units

• Primary motor cortex is in the parietal lobe.
• Motor Unit: # of muscle fibers per motor neuron
• Large motor units have decreased control, found in back muscles
• Small motor units have increased control, found in face and hands

Roles of Muscle Contraction

• Agonist (prime mover): generates most force
• Antagonist (larger): opposes the action of agonist
• Synergist (small): assists the agonists
• Fixator: stabilizes the joints

Relevance to Fitness

• Cuing Movement: information from somatosensory system, learning a new skill, PNF stretching.
• Plyometrics: ballistic movements, rapid muscle stretch, activate excitatory stretch reflex and increased muscle force
• Instability training: increased activation of synergist/fixator muscles, decreased injury

Approaches to Avoid Plateaus

• Exercise type (switching from open chain to closed chain exercises)
• Eccentric focus (eccentric contractions to increase hypertrophy)
• Pyramids (beginners warm up, heavy load, and medium reps)

Functional Anatomy

• Functional anatomy focuses on musculoskeletal significance within a movement setting.
• Active ROM (person performs movement) vs Passive ROM (someone performs the movement). Classification of end feel and limiter (bony, capsular, approximation and abnormal)

Explore the intricate workings of the human cardiovascular system in this quiz. Delve into blood flow, heart structure, and electrical conduction, as well as understand the importance of cardiac output. Perfect for students studying human biology or health sciences.