Applied anatomy and physiology

Welcome to Applied Anatomy and Physiology!

Ever wondered how your body manages to sprint for a ball, kick a goal, or stay balanced on a beam? This chapter is all about the "engine" and the "frame" of your body. We are going to look at how your bones, muscles, heart, and lungs work together to make physical activity possible. Don't worry if it seems like a lot of names to learn – we will break it down step-by-step with simple tricks to help you remember!

1.1 The Musculo-Skeletal System

Think of your skeleton as the frame of a house. Without it, you’d just be a pile of skin and organs on the floor! But it does much more than just hold you up.

Functions of the Skeleton

There are six main jobs the skeleton does to help you perform in sport:

• Protection: Hard bones protect vital organs (e.g., your cranium protects your brain during a header in football).
• Muscle Attachment: Bones give muscles a place to grip so they can pull and create movement.
• Joints for Movement: Where bones meet, they form joints that allow you to run, jump, and throw.
• Blood Cell Production: Red blood cells (carry oxygen) and white blood cells (fight infection) are made in the bone marrow.
• Platelets: These are produced in the bone marrow and help your blood clot if you get a scrape on the pitch.
• Storage of Minerals: Bones store calcium and phosphorus to keep them strong.

Quick Review: Remember the "Five S's and a P" (Support, Shape, Shelter/Protection, Storage, Sport/Movement, and Production of blood).

Classification of Bones

Bones come in different shapes because they have different jobs:

• Long Bones: Like the femur (thigh) or humerus (arm). They act as levers to help you move quickly.
• Short Bones: Like tarsals (ankle) or carpals (wrist). They are great for weight-bearing.
• Flat Bones: Like the ribs or cranium. They offer protection and a wide area for muscles to attach.
• Irregular Bones: Like the vertebrae. They have unique shapes for protection and muscle attachment.

The Major Bones You Need to Know

You need to be able to identify these on a diagram. Let's group them:

• The Head and Core: Cranium (skull), Clavicle (collar bone), Scapula (shoulder blade), Ribs, Sternum (chest bone), Pelvis (hips).
• The Spine (Vertebral Column): It has five regions (from top to bottom): Cervical, Thoracic, Lumbar, Sacrum, Coccyx.
• The Arms: Humerus (top), Radius and Ulna (bottom - the Radius is on the thumb side!), Carpals, Metacarpals, Phalanges.
• The Legs: Femur (top), Patella (knee cap), Tibia and Fibula (bottom - the Tibia is the 'thick' shin bone), Tarsals, Metatarsals, Phalanges.

Common Mistake: Students often mix up the Tibia and Fibula. Remember: The Tibia is Thick and Tough (the main shin bone).

Joints and Movement

A joint is where two or more bones meet. Different joints allow different "Movement Possibilities":

• Ball and Socket (Hip and Shoulder): Allows the most movement, including rotation and circumduction (moving in a circle).
• Hinge (Knee, Elbow, Ankle): Works like a door hinge. Allows flexion (bending) and extension (straightening).
• Pivot (Neck): Allows rotation (turning your head to see a teammate).
• Condyloid (Wrist): Allows movement side-to-side and up-and-down.

Specific Ankle Movements:

• Plantar-flexion: Pointing your toes (like a ballerina or kicking a ball).
• Dorsi-flexion: Pulling your toes up toward your shin.

Connective Tissues

• Ligaments: Connect Bone to Bone. They keep joints stable.
• Tendons: Connect Muscle to Bone. They pull on the bone to make you move.

Memory Aid: "Ligaments for Like to Like" (Bone to Bone).

The Muscular System

Muscles are the "motors" that pull your bones. There are three types:

• Voluntary: Muscles you control (e.g., Biceps).
• Involuntary: Muscles that work automatically (e.g., in blood vessels).
• Cardiac: The special muscle that makes up your heart.

Antagonistic Pairs: Muscles never work alone; they work in pairs. When one contracts (shortens), the other relaxes (lengthens).

• The muscle that is working is the Agonist.
• The muscle that is relaxing is the Antagonist.
• Example: When you perform a bicep curl, the Biceps is the Agonist and the Triceps is the Antagonist.

Muscle Fiber Types:

• Type I (Slow Twitch): Deep red color. They don't tire easily. Good for marathon runners.
• Type IIa (Fast Twitch): For speed, strength, and power. Good for 400m runners.
• Type IIx (Fast Twitch): Very fast and powerful, but tire very quickly. Good for 100m sprinters.

Key Takeaway: The skeletal system provides the structure, and the muscular system provides the power. They work together as a musculo-skeletal system to create sporting movement.

1.2 The Cardio-Respiratory System

This is your body's delivery service. It takes Oxygen to your muscles and carries away Carbon Dioxide waste.

The Cardiovascular System (The Heart and Blood)

Your heart is a double-pump system. It has four chambers:

• Atria: The two upper chambers (they receive blood).
• Ventricles: The two lower chambers (they pump blood out).
• Valves: (Tricuspid, Bicuspid, Semi-lunar) These act like one-way trapdoors to stop blood flowing backward.
• Septum: The wall that divides the left and right sides of the heart.

Blood Vessels:

• Arteries: Carry blood Away from the heart. They have thick, elastic walls because the blood is under high pressure.
• Veins: Carry blood Into the heart. They have valves to keep blood moving in the right direction.
• Capillaries: Tiny vessels where oxygen and nutrients pass into the muscles.

Redistribution of Blood (Vascular Shunting): When you exercise, your body is smart. It uses Vasodilation (widening of vessels) to send more blood to your working muscles and Vasoconstriction (narrowing of vessels) to take blood away from places that don't need it right now, like your stomach.

The Respiratory System (The Lungs)

Air travels: Nose/mouth -> Trachea -> Bronchi -> Bronchioles -> Alveoli.

The Alveoli are tiny air sacs where Gas Exchange happens. Oxygen enters the blood, and Carbon Dioxide leaves it.

Breathing Terms:

• Tidal Volume: The amount of air you breathe in or out in a normal breath. This increases during exercise.
• Vital Capacity: The maximum amount of air you can breathe out after breathing in as much as you can.

Key Takeaway: The heart pumps the blood, and the lungs provide the oxygen. During exercise, your heart rate and breathing depth increase to get more "fuel" to the muscles.

1.3 Aerobic and Anaerobic Exercise

How does your body turn food into energy? It depends on whether oxygen is present.

Aerobic Exercise (With Oxygen)

For long, low-intensity activities (like jogging).
Formula: \( \text{Glucose} + \text{Oxygen} \rightarrow \text{Energy} + \text{Carbon Dioxide} + \text{Water} \)

Anaerobic Exercise (Without Oxygen)

For short, high-intensity bursts (like a 50m sprint). Because there isn't enough oxygen, your body produces a waste product called Lactic Acid.
Formula: \( \text{Glucose} \rightarrow \text{Energy} + \text{Lactic Acid} \)

Energy Sources:

• Carbohydrates: The main fuel for both aerobic and anaerobic exercise.
• Fats: Used only for low-intensity, aerobic exercise.

1.4 The Short- and Long-Term Effects of Exercise

Short-term Effects (During Exercise)

• Lactate Accumulation: Lactic acid builds up in the muscles, causing that "burning" feeling and fatigue.
• Heart Rate (HR): Increases to pump blood faster.
• Stroke Volume (SV): The amount of blood pumped out of the heart in one beat increases.
• Cardiac Output (Q): The total amount of blood pumped in one minute increases.

The Equation: \( \text{Cardiac Output (Q)} = \text{Stroke Volume (SV)} \times \text{Heart Rate (HR)} \)

Long-term Effects (Adaptations)

If you train regularly for weeks/months, your body changes:

• Hypertrophy: Your heart and muscles get bigger and stronger.
• Bradycardia: Your resting heart rate gets lower because your heart is more efficient.
• Increased Capilliarisation: More tiny blood vessels grow around the muscles and alveoli.
• Bone Density: Your bones get thicker and stronger.

Quick Review: Short-term = what happens now (sweating, fast HR). Long-term = how you improve (stronger heart, lower resting HR).

Did you know? Elite athletes often have a resting heart rate below 50 beats per minute! This is because their Stroke Volume is so high that their heart doesn't need to beat as often to move the same amount of blood.