Exploring the Muscular System

Muscular System

Components & Functions

• Skeletal muscles facilitate voluntary movement, posture, and heat production providing bodily support and mobility.
• Smooth muscles enable involuntary control, such as digestion and blood vessel regulation critical for internal bodily functions.
• Cardiac muscle drives involuntary contractions to pump blood throughout the body, essential for circulation.
• Tendons connect muscles to bones, enabling the transmission of force for movement.

Types of Muscles

• Voluntary muscles, such as biceps and quadriceps, exhibit a striped (striated) appearance and are consciously controlled.
• Involuntary muscles, like the heart (cardiac) and intestines, appear smooth or branched and operate unconsciously.

Types of Muscular Contractions

• Isotonic eccentric contraction involves muscle lengthening under tension, like lowering a dumbbell during a bicep curl.
• Isotonic concentric contraction occurs when a muscle shortens to generate force such as lifting a dumbbell.
• Isometric contraction happens when muscle contracts without a change in length like holding a plank, engaging the abdominals.

Agonist vs. Antagonist

• Agonist muscles are the prime movers that create movement; biceps during elbow flexion exemplify this function.
• Antagonist muscles oppose the agonist, controlling movement such as the triceps during elbow flexion.

Muscle Fibre Types

• Slow Twitch (Type 1) muscle fibers are suited for endurance activities and are fatigue-resistant, ideal for marathon running.
• Fast Twitch (Type 2) muscle fibers generate explosive power but fatigue quickly, making them ideal for sprinting and weightlifting.
• Genetics influence inherited fibre distribution, affecting athletic predispositions.
• Training (endurance vs. power sports) impacts muscle fibre development and performance.
• Muscle location affects fibre composition, e.g., calves versus arms, influencing physical capabilities.

Skeletal System

Functions

• Support is provided through the structural framework of the skeletal system.
• Protection is offered by shielding organs like ribs protecting the lungs and heart.
• Movement is facilitated as bones act as levers for muscles.
• Hematopoiesis is the production of blood cells in bone marrow.
• Mineral storage stores calcium and phosphorus.

Types of Bones

• Long bones, like the femur and humerus, act as levers for movement, enabling large-scale motions.
• Short bones, such as carpals in the wrist, are cube-shaped, providing shock absorption.
• Flat bones, including the scapula and sternum, feature broad surfaces for protection.
• Irregular bones, like vertebrae, have complex shapes, serving specific functions.
• Sesamoid bones, such as the patella (kneecap), are embedded in tendons, providing mechanical advantages.

Vertebral Column

• Cervical vertebrae are located in the neck with a total of 7.
• Thoracic vertebrae are located in the upper back with a total of 12.
• Lumbar vertebrae are located in the lower back with a total of 5.
• Sacral vertebrae are located in the pelvis (fused) with a total of 5.
• Coccyx vertebrae are located in the tailbone (fused) with a total of 4.

Types of Joints

• Fibrous joints are immovable, with no cavity, such as skull sutures, which provide stability.
• Cartilaginous joints are semi-movable, featuring cartilage connections like ribs to the sternum, allowing limited movement.
• Synovial joints are freely movable, containing a fluid-filled cavity like the knee and shoulder, to facilitate extensive movement.

Synovial Joints

• Hinge joints allow flexion and extension along one axis and are exemplified by the elbow.
• Ball and Socket joints permit multi-axial rotation, like in the shoulder and hip, offering versatile movements.
• Saddle joints enable angular movement, specific to the thumb (carpometacarpal) for grasping.
• Condyloid joints facilitate two-axis movement without rotation, as seen in the wrist, allowing complex motions.
• Pivot joints enable rotational movement, such as in the atlas/axis (neck), allowing head rotation.
• Gliding joints permit sliding motion, found in the ankle and wrist, enabling flexibility.

Cardiovascular System

Functions

• Circulation of oxygen and nutrients through the body's tissues.
• Removal of carbon dioxide and wastes from the body.
• Regulation of body temperature.
• Transportation of hormones and immune cells

Blood Flow Through the Heart

• The right atrium receives deoxygenated blood, which passes through the tricuspid valve into the right ventricle, then flows to the lungs via the pulmonary artery to become oxygenated.
• Oxygenated blood enters the left atrium, moves through the bicuspid valve into the left ventricle, and is pumped out to the body via the aorta.

Types of Blood Vessels

• Arteries carry oxygenated blood and have thick, muscular walls to withstand high pressure.
• Veins carry deoxygenated blood and have thin walls with valves to prevent backflow.
• Capillaries are the site of gas and nutrient exchange with microscopic, thin walls to facilitate diffusion.

Respiratory System

Functions

• Gas exchange occurs which facilitates oxygen intake and carbon dioxide removal.
• Filters and warms inhaled air to protect the lungs.
• Enables vocalization through the movement of air over the vocal cords.

Airflow Pathway

• Air enters through the nose and proceeds through the nasal cavity, pharynx, larynx, trachea, bronchi, and lungs, finally reaching the alveoli where gas exchange occurs.

First Aid & CPR

First Aid Definition

• This is the immediate care given for injuries or illnesses to stabilize a person until professional medical help arrives.

DRS ABCD

• D: Check for Danger to ensure the safety of both the responder and the casualty, preventing further harm.
• R: Assess Response (consciousness) by checking if the person is responsive through verbal or tactile stimuli.
• S: Send for help by calling emergency services (000) to ensure professional medical assistance is on its way.
• A: Clear Airway to ensure unobstructed breathing by removing any obstructions in the mouth and throat.
• B: Check Breathing to determine if the person is breathing normally; if not, artificial respiration may be needed.
• C: Start CPR (30:2 compressions:breaths) to maintain blood circulation and oxygen supply to vital organs.
• D: Use Defibrillator (AED) if available to deliver an electrical shock that can restore a normal heart rhythm.

RICER

• R: Rest the injury to prevent further damage and promote healing.
• I: Apply Ice to reduce swelling and alleviate pain.
• C: Use Compression (bandage) to support the injured area and minimize swelling.
• E: Elevate the injured area above heart level to reduce swelling.
• R: Refer to a medical professional for proper diagnosis and treatment.

CPR Compression Ratio

• 30 compressions : 2 breaths is the standard ratio for adults during CPR to maintain circulation and oxygenation.

CPR Stands For

• Cardiopulmonary Resuscitation is an emergency procedure that combines chest compressions with artificial ventilation to preserve brain function until further measures are taken to restore spontaneous circulation and breathing in a person who is in cardiac arrest.