Basic Anatomy: definition & Terminologies

The human body is a complex and fascinating structure composed of various systems that work together to sustain life. Understanding the basic anatomy of the human body provides insight into its remarkable functions and capabilities.

The human body can be divided into several major regions:

• Head and Neck: This region includes the brain, enclosed within the skull, which controls all bodily functions. The face houses the sensory organs, such as the eyes, ears, nose, and mouth. The neck connects the head to the torso and contains the trachea (windpipe) and esophagus (food pipe).
  
  Human Head and Neck Anatomy

• Torso (Trunk): This central part of the body houses vital organs. The thorax contains the heart and lungs, protected by the ribcage. The abdomen contains organs like the stomach, liver, intestines, kidneys, and pancreas, which are involved in digestion and other essential processes. The pelvis contains the reproductive organs and the bladder.
  
  Human Torso Anatomy

• Upper Limbs (Arms): The arms consist of the shoulder, upper arm (humerus), forearm (radius and ulna), wrist, and hand. These structures facilitate a wide range of movements and manipulation of objects.
  
  Human Upper Limb Anatomy

• Lower Limbs (Legs): The legs consist of the hip, thigh (femur), lower leg (tibia and fibula), ankle, and foot. These structures provide support, balance, and enable locomotion.
  
  Human Lower Limb Anatomy

The human body is composed of various organ systems, each performing specific functions:

• Skeletal System: Provides support, protection, and framework for the body. It consists of bones, cartilage, and ligaments.
  
  Human Skeletal System

• Muscular System: Enables movement, maintains posture, and generates heat. It consists of various types of muscles.
  
  Human Muscular System

• Nervous System: Controls bodily functions, receives and processes sensory information, and coordinates responses. It includes the brain, spinal cord, and nerves.
  
  Human Nervous System

• Circulatory System: Transports oxygen, nutrients, and hormones throughout the body and removes waste products. It includes the heart, blood vessels, and blood.
  
  Human Circulatory System

• Respiratory System: Takes in oxygen and expels carbon dioxide. It includes the lungs, trachea, and bronchi.
  
  Human Respiratory System

• Digestive System: Breaks down food, absorbs nutrients, and eliminates waste. It includes the mouth, esophagus, stomach, intestines, liver, and pancreas.
  
  Human Digestive System

• Endocrine System: Produces hormones that regulate various bodily functions. It includes glands like the pituitary, thyroid, adrenal glands, and pancreas.
  
  Human Endocrine System

• Urinary System: Filters waste products from the blood and produces urine. It includes the kidneys, ureters, bladder, and urethra.
  
  Human Urinary System

• Reproductive System: Responsible for reproduction. It includes the testes and penis in males and the ovaries, uterus, and vagina in females.
  
  Human Reproductive System

Understanding the basic anatomy of the human body provides a foundation for comprehending its complex functions, maintaining health, and appreciating the intricate design that enables us to live, move, and interact with the world around us.

Gross anatomy

Gross anatomy, also known as macroscopic anatomy or topographical anatomy, is the branch of anatomy that deals with the study of biological structures that are visible to the naked eye. This means structures that can be seen without the use of a microscope.

Gross anatomy can be studied through:

• Dissection: This involves surgically opening an organism (plant, animal, or human cadaver) and examining its organs and structures.

• Non-invasive methods: These include medical imaging techniques like X-rays, CT scans, MRI scans, and ultrasound.

• Endoscopy: This involves inserting a thin tube with a camera into the body through a small incision to examine internal organs.

Gross anatomy helps us understand the larger structures of organs and organ systems, their relationships, and how they work together to maintain the functions of life. It is a fundamental subject for medical professionals, biologists, and anyone interested in the structure and function of living organisms.

Skeletal system - Bones and Joints

What are bones, muscles and joints?

Bones, muscles and joints make up the musculoskeletal system, along with cartilage, tendons and ligaments. This system gives your body its structure and support, lets you move around and protects important organs.

Injuries and many illnesses can damage bones, muscles and joints.

Parts of the musculoskeletal system

There are many different elements that make up the musculoskeletal system:

1. Skeleton — this is the framework of the body. The adult human skeleton is made up of 206 bones.

2. Joints — an area where 2 bones work together.

3. Cartilage — is a cushioning that covers the ends of 2 bones.

4. Ligaments — tough bands of tissue that join bones to other bones to strengthen joints.

5. Muscles — there are more than 600 skeletal muscles in the human body. They help the body move.

6. Tendons — these are made of strong fibrous connective tissue and they attach muscles to bones.

What is the role of bones in the human body?

Bones give people shape. They hold your body upright and protect internal organs (like the heart and the liver) from injury and help you to move.

Bones are strong tissues made of collagen (a protein that forms a flexible framework) and calcium phosphate (a mineral that makes them strong and hard).

Most bone growth happens during your childhood and teenage years. 

The spine or vertebral column is the central support of your body, helping you walk, move, twist and bend. It has 33 bones called vertebrae, separated by discs. It carries all the nerve signals from the brain to the rest of the body and sensory input from the body back to the brain.

What is the role of muscles in the human body?

There are 3 different types of muscle, each with different functions that help your body move and function well. These are:

• skeletal muscles

• smooth muscles

• cardiac (heart) muscles

Skeletal muscle

Skeletal muscle is a voluntary muscle, which means that you can consciously control its movement. As well as helping you to move, these muscles also help generate heat in the body, protect organs and help maintain your posture.

Skeletal muscles are usually attached to the bone by tendons. When you want to move, your brain tells a muscle to contract, it shortens, pulling one bone towards another across a joint. Skeletal muscles work in pairs — when one shortens, a corresponding muscle lengthens. For example, when you contract your bicep on the front of your upper arm, your tricep on the back of your upper arm lengthens.

Physical activity maintains or increases the strength of your muscles.

Smooth muscle

Smooth muscle is found inside blood vessels and organs like the intestines. You can’t consciously control smooth muscle — these muscles are contract and relax often without you even realising they are working. For example, smooth muscles contract to move food and stool through your digestive system and in your arteries and veins to help regulate your blood pressure.

Cardiac muscle

The heart is made of special muscle called cardiac muscle. You can’t control it consciously. It contracts to make your heart beat, and is controlled by your heart’s inbuilt pacemaker — the sinoatrial node.

What is the role of joints in the human body?

Joints connect between the bones, and allow them to move. There are three different types of joints:

• synovial

• cartilaginous

• fibrous

What are synovial joints?

Synovial joints are the most common type of joints and are found in your arms and legs. The ends of your bones are covered with cartilage and separated by the joint cavity, which is filled with a thick gel called synovial fluid. Synovial fluid helps to lubricate the cartilage and provides nourishment.

What are cartilaginous joints?

Joints in the spine, pelvis and between the ribs and the sternum are cartilaginous joints. They provide more stability but not as much movement. The bones are connected by cartilage in this type of joint.

What are fibrous joints?

Fibrous joints allow no movement — just stability. They are held together by strong fibrous connective tissue. You have fibrous joints in your skull.

Conditions and injuries affect the bones

• fractures — where a bone is broken

• osteopaenia and osteoporosis — conditions where bone density is reduced and fractures become more likely

• Paget's disease — a disease that weakens and deforms bones

• bone cancer — either cancer that starts in the bones (primary bone cancer) or cancer that spreads to the bones from somewhere else in the body (secondary bone cancer)

• rickets — a bone disease affecting children, caused by low vitamin D levels

• osteomyelitis (bone infection) — usually caused by bacteria

Many conditions can affect your joints. Arthritis, which is characterised by joint pain and stiffness, is one of the most common. Different types of arthritis have different causes. Some conditions that can affect the joints are:

• osteoarthritis — this type of arthritis is more common as you get older and most often affects the knees, hips, finger joints and big toe joint

• rheumatoid arthritis — an autoimmune disease where the immune system attacks the lining of the joints

• septic arthritis — a type of arthritis caused by an infection (usually bacterial)

• psoriatic arthritis — a type of inflammatory arthritis which affects people who have psoriasis

• gout — a painful condition where small crystals of uric acid form in the joints, causing pain, redness and inflammation

• ankylosing spondylitis — a condition affecting the joints of the neck, spine and pelvis, causing back pain

• sprains — where the ligaments that connect and stabilise the bones in a joint are stretched or torn

Muscles- Skeletal and brief understanding of smooth and cardiac muscles.

Skeletal Muscle

Skeletal muscles are the muscles that are attached to your bones and allow you to move. They are voluntary muscles, meaning you can consciously control their movement. Skeletal muscles are striated, which means they have a striped appearance under a microscope. This is due to the arrangement of protein filaments within the muscle fibers.

• Function: Movement, posture, and heat production

• Location: Attached to bones via tendons

• Appearance: Striated (striped)

• Control: Voluntary (conscious control)

Smooth Muscle

Smooth muscles are found in the walls of hollow organs like your stomach, intestines, and blood vessels. They are involuntary muscles, meaning you cannot consciously control their movement. Smooth muscles are not striated, and their contractions are typically slower and more sustained than skeletal muscle contractions.

• Function: Movement of substances through organs (e.g., digestion, blood flow)

• Location: Walls of hollow organs

• Appearance: Non-striated (smooth)

• Control: Involuntary (unconscious control)

Cardiac Muscle

Cardiac muscle is a special type of muscle found only in the heart. It is involuntary and striated. Cardiac muscle cells are connected by intercalated discs, which allow for coordinated contractions that pump blood throughout the body.

• Function: Pumping blood

• Location: Heart

• Appearance: Striated (striped)

• Control: Involuntary (unconscious control)

Unit 2 Basic Physiology: Definition and terminologies

Physiology is the scientific study of the functions and processes of living organisms and their parts. It seeks to understand how organisms, from the smallest cells to complex organ systems, work together to maintain life.

• Anatomy: The study of the structure and organization of living organisms.

• Homeostasis: The ability of an organism to maintain a stable internal environment despite external changes.

• Cell: The basic structural and functional unitof all living organisms.

• Tissue: A group of similar cells that work together to perform a specific function.

• Organ: A structure composed of different tissues that work together to perform a complex function.

• Organ System: A group of organs that work together to perform a major bodily function.

• Metabolism: The sum of all chemical reactions that occur within an organism.

• Catabolism: The breakdown of complex molecules into simpler ones, releasing energy.

• Anabolism: The synthesis of complex molecules from simpler ones, requiring energy.

Organ Systems

The human body is organized into several major organ systems, each with a specific function:

• Integumentary System: Skin, hair, nails (protection, temperature regulation)

• Skeletal System: Bones, joints (support, protection, movement)

• Muscular System: Muscles (movement, posture, heat production)

• Nervous System: Brain, spinal cord, nerves (communication, control)

• Endocrine System: Glands, hormones (regulation of bodily functions)

• Cardiovascular System: Heart, blood vessels (transport of oxygen and nutrients)

• Lymphatic System: Lymph nodes, vessels (immune response, fluid balance)

• Respiratory System: Lungs, airways (gas exchange)

• Digestive System: Stomach, intestines, liver, pancreas (breakdown of food, absorption of nutrients)

• Urinary System: Kidneys, bladder (removal of waste products)

• Reproductive System: Testes, ovaries (production of gametes, reproduction)

Understanding Physiology

Physiology is a complex and fascinating field that explores how our bodies work. It is essential for understanding health and disease, developing new treatments, and improving our quality of life. By mastering the basic terminologies and concepts of physiology, you will gain a deeper understanding of how your body functions and how it interacts with the world around you.

Major Systems of the Human Body  

1. Circulatory System:

Function: Transports oxygen, nutrients, and hormones to cells; removes waste products like carbon dioxide.

Key Organs: Heart (pump), blood vessels (arteries, veins, capillaries), blood (red blood cells, white blood cells, platelets, plasma).

Interesting Facts:

The average adult heart beats about 100,000 times a day.

If you laid out all the blood vessels in an adult end-to-end, they would stretch for about 60,000 miles.

2. Digestive System:

Function: Breaks down food into nutrients the body can absorb; eliminates waste.

Key Organs: Mouth, esophagus, stomach, small intestine, large intestine, liver, pancreas, gallbladder.

Interesting Facts:

The small intestine is about 22 feet long in an adult.

The digestive process can take anywhere from 24 to 72 hours.

3. Musculoskeletal System:

Function: Provides support, shape, and movement to the body; protects internal organs.

Key Components: Bones (skeleton), muscles, tendons (connect muscle to bone), ligaments (connect bone to bone), joints.

Interesting Facts:

The human body has 206 bones.

The strongest muscle in the human body is the masseter (jaw muscle).

4. Nervous System:

Function: Controls and coordinates body functions; senses and responds to internal and external stimuli.

Key Components: Brain, spinal cord, nerves (neurons).

Interesting Facts:

The brain is the most complex organ in the human body.

Nerve impulses can travel at speeds of up to 268 miles per hour.

5. Respiratory System:

Function: Takes in oxygen and releases carbon dioxide (gas exchange).

Key Organs: Nose, pharynx, larynx, trachea, bronchi, lungs.

Interesting Facts:

The surface area of the lungs is roughly the same size as a tennis court.

An average person breathes about 20,000 times a day.

Key Points 

Interconnectedness: Emphasize how these systems work together to maintain overall health.

Health and Wellness: Discuss how lifestyle choices (diet, exercise, sleep) impact the function of these systems.

Curiosity: Encourage students to ask questions and explore further details about each system.

Exercise Physiology

The study of the body's responses to physical activity. These responses include changes in metabolism,  cardiovascular function (heart and blood vessels), respiratory function (lungs), muscle function, and the nervous system. It also involves understanding how the body adapts to repeated exercise over time.  

Physiological responses of the circulatory and respiratory systems to exercise:

Circulatory System Responses:

• Increased Cardiac Output: The heart pumps more blood per minute to meet the increased oxygen and nutrient demands of working muscles. This is achieved by:

• Increased Heart Rate: The number of beats per minute rises.

• Increased Stroke Volume: The amount of blood pumped with each beat increases.

• Redistribution of Blood Flow: Blood is directed away from organs that are less essential during exercise (like the digestive system) and towards working muscles.   

• Vasodilation in Active Muscles: Blood vessels in active muscles widen to increase blood flow and deliver more oxygen and nutrients.   

• Vasoconstriction in Non-Active Tissues: Blood vessels in non-active tissues narrow to redirect blood to where it's needed most.   

• Increased Blood Pressure: Systolic blood pressure (the pressure when the heart contracts) rises due to the increased cardiac output.

Respiratory System Responses:

• Increased Ventilation: The rate and depth of breathing increase to bring in more oxygen and expel more carbon dioxide.

• Increased Tidal Volume: The amount of air inhaled and exhaled with each breath increases.   

• Increased Respiratory Rate: The number of breaths per minute rises.

• Increased Gas Exchange: Oxygen uptake and carbon dioxide removal in the lungs increase to match the increased metabolic demands of the body.   

• Bronchodilation: Airways widen to facilitate airflow.

• Increased Blood Flow to the Lungs: Pulmonary blood vessels dilate to accommodate the increased blood flow from the heart.   

Combined Effects:

The circulatory and respiratory systems work together during exercise. The respiratory system takes in oxygen and releases carbon dioxide, while the circulatory system transports these gases to and from the tissues. The increased ventilation and blood flow to the lungs during exercise ensure that the muscles receive the oxygen they need to produce energy and that carbon dioxide is efficiently removed.   

 Temperature regulation and the environment's influence:

Temperature Regulation:

The human body strives to maintain a core temperature of around 37°C (98.6°F) for optimal functioning.

 This delicate balance is known as thermoregulation, achieved through intricate physiological processes.   

Mechanisms of Heat Production:

• Metabolism: Basic metabolic activities generate heat as a byproduct.   

• Shivering: Involuntary muscle contractions generate heat.

• Hormonal Thermogenesis: Hormones like thyroxine and adrenaline can increase metabolic rate, boosting heat production.   

• Physical Activity: Exercise significantly elevates heat production.   

Mechanisms of Heat Loss:

• Radiation: Heat radiates from the body to cooler surroundings.   

• Conduction: Direct contact with a cooler surface transfers heat.

• Convection: Air currents carry away heat from the skin.   

• Evaporation: Sweat evaporates from the skin, cooling the body (most effective in dry climates).   

Environmental Impact:

The environment plays a crucial role in how the body regulates temperature:

• Ambient Temperature:

• Hot Environments: Trigger sweating and increased blood flow to the skin for cooling.

• Cold Environments: Trigger shivering, vasoconstriction in the skin, and seeking warmth to conserve heat.

• Humidity: High humidity reduces the effectiveness of evaporative cooling, making hot weather feel even hotter.   

• Wind: Wind chill can accelerate heat loss, making cold temperatures feel even colder.   

• Sunlight: Direct sunlight adds to heat gain, especially on hot days.   

• Clothing: Proper clothing helps regulate heat exchange. In cold weather, layering traps heat. In hot weather, light-colored, loose clothing reflects sunlight and allows for air circulation.   

Examples of Environmental Impact:

• Heatstroke: A dangerous condition where the body overheats due to prolonged exposure to high temperatures and humidity.   

• Hypothermia: A potentially fatal condition where the body's core temperature drops dangerously low due to prolonged exposure to cold.   

• Dehydration: Can occur more rapidly in hot environments, further impairing temperature regulation.   

• Frostbite: Occurs when tissues freeze due to extreme cold.   

By understanding how the environment impacts temperature regulation, we can better protect ourselves and others from heat and cold-related illnesses. It also highlights the importance of adapting our behaviors (e.g., clothing choices, activity levels, and hydration) to different environmental conditions.

VO₂ Max (Maximal Oxygen Uptake)

• Definition: The maximum amount of oxygen your body can utilize during intense exercise.

• Significance: A high VO₂ max indicates better cardiovascular fitness and endurance capacity.

• Training Adaptation: Primarily improved by aerobic exercise (running, swimming, cycling).

Strength 

Definition: Exercise aimed at increasing muscle strength and power.

Significance: Enhances muscle mass, bone density, and metabolic rate.

Training Adaptation: Primarily improved by resistance exercises (weightlifting, bodyweight exercises).

Benefits of  Training

Enhanced Performance: Improved endurance, strength, and power.

Injury Prevention: Stronger muscles and better movement patterns can reduce injury risk.

Overall Health: Improved cardiovascular health, metabolic function, and body composition.

Important Considerations

Training Experience: Beginners may see greater initial gains in both VO₂ max and strength.

Genetics: Individual genetic factors can influence the rate and magnitude of adaptation.

Nutrition: Proper nutrition is crucial for supporting training adaptations and recovery.

Exercise Biochemistry

Exercise biochemistry delves into the chemical processes and reactions that occur within the body during physical activity. It explores the roles of macronutrients, vitamins, and minerals in energy production, muscle function, and overall exercise performance.

Metabolism of Macronutrients

• Carbohydrates: The primary energy source during exercise. They are broken down into glucose, which is used to produce ATP (adenosine triphosphate), the body's energy currency. Excess glucose is stored as glycogen in the liver and muscles.

• Fats: Used as an energy source during low- to moderate-intensity exercise. They are stored as triglycerides and broken down into fatty acids to produce ATP.

• Protein: Primarily used for muscle building and repair, but can also be used as an energy source in extreme cases when carbohydrate and fat stores are depleted.

Vitamins and Minerals

• Vitamins: Essential for energy metabolism. They play key roles in the breakdown of carbohydrates, fats, and proteins to produce ATP.

• Vitamin C: A powerful antioxidant that helps protect cells from damage caused by exercise.

• Vitamin D: Important for bone health and muscle function.

• Calcium: Crucial for muscle contraction and nerve function.

• Iron: Necessary for transporting oxygen to working muscles.

• Magnesium: Involved in energy production and muscle relaxation.

• Sodium, Potassium, Chloride: Electrolytes that help maintain fluid balance and nerve function.

Neural Control of Movement and Muscle Activity

• Core Components:

  • Central Nervous System (CNS): Brain and spinal cord.

  • Peripheral Nervous System (PNS): Nerves outside the CNS.

    • Motor Nerves: Carry signals from the CNS to muscles.

    • Sensory Nerves: Carry information from sensory receptors to the CNS.

  • Muscles: Effectors that produce movement.

• Key Players:

  • Motor Cortex: Part of the brain responsible for planning and initiating voluntary movement.

  • Spinal Cord: Relays signals between the brain and muscles, and also houses reflex circuits for quick, automatic responses.

  • Motor Neurons (Motoneurons): Nerve cells that transmit signals from the spinal cord to muscle fibers.

  • Muscle Fibers: Cells that contract in response to signals from motor neurons.

Types of Movement:

• • Voluntary: Conscious, deliberate actions (e.g., walking, writing).

  • Reflexes: Automatic, involuntary responses to stimuli (e.g., knee-jerk reflex).

Related Sciences  

• Neuroscience: The study of the nervous system.

• Motor Control: A subfield of neuroscience focused on how the brain and spinal cord control movement.

• Muscle Physiology: The study of how muscles function.

• Kinesiology: The study of human movement.

Portions for First Internal ends

Exercise metabolism involves the complex interplay of carbohydrates, lipids, and proteins to provide energy for muscle contraction and sustain physical activity. 

Carbohydrates

• Primary Fuel Source: Carbohydrates, stored as glycogen in muscles and the liver, are the primary energy source for most types of exercise, especially high-intensity activities.

• Glycolysis: During exercise, glycogen is broken down into glucose, which undergoes glycolysis to produce ATP (adenosine triphosphate), the energy currency of cells.

Lipids (Fats)

• Energy Reserve: Lipids, stored as triglycerides in adipose tissue and muscle, provide a vast energy reserve.

• Fat Oxidation: During exercise, triglycerides are broken down into fatty acids, which undergo beta-oxidation to produce ATP.

• Aerobic Metabolism: Fat oxidation primarily occurs during aerobic exercise, particularly at lower intensities and longer durations.

• Endurance Activities: Lipids become the predominant fuel source during prolonged endurance activities, sparing glycogen stores.

Proteins

• Minor Role: Proteins play a relatively minor role in energy provision during exercise compared to carbohydrates and lipids.

• Muscle Repair and Growth: Proteins are essential for muscle repair and growth following exercise.

Factors Influencing Fuel Utilization

• Exercise Intensity and Duration: Higher intensity exercise relies more on carbohydrates, while lower intensity exercise utilizes more fat. As exercise duration increases, fat utilization increases.

• Training Status: Trained individuals can utilize fat more efficiently, sparing glycogen stores and delaying fatigue.

• Dietary Intake: Carbohydrate availability influences glycogen stores and its utilization during exercise.

• Hormones: Hormones like insulin, glucagon, epinephrine, and cortisol regulate fuel mobilization and utilization during exercise.

Key Points:

• Carbohydrates and fats are the primary energy sources during exercise.

• The relative contribution of each fuel depends on exercise intensity, duration, training status, and diet.

• Proteins play a minor role in energy provision but are vital for muscle repair and growth.

Sports Nutrition: Macro and Micronutrients

Why is nutrition important?

• Provides Energy: Fuels your muscles for training and competition

• Aids Recovery: Repairs tissues damaged during exercise

• Boosts Immunity: Helps your body fight off infections

• Supports Overall Health: Maintains well-being and improves performance

Macronutrients

• Carbohydrates:

  • Primary fuel source for exercise

  • Found in grains, fruits, vegetables, and legumes

  • 4 calories per gram

• Proteins:

  • Builds and repairs muscles

  • Found in meat, poultry, fish, eggs, dairy, and beans

  • 4 calories per gram

• Fats:

  • Concentrated energy source and helps absorb vitamins

  • Found in oils, nuts, seeds, avocado, and fatty fish

  • 9 calories per gram

Micronutrients

• Vitamins and Minerals:

  • Support various bodily functions, including energy production, immune function, and bone health

  • Found in a variety of foods, including fruits, vegetables, whole grains, and lean proteins

Hydration

• Water:

  • Essential for maintaining body temperature, transporting nutrients, and removing waste products

  • Drink plenty of water before, during, and after exercise

Pre, During, and Post-Exercise Nutrition

• Pre-Exercise:

  • Focus on carbohydrates for energy

  • Eat a meal or snack 1-4 hours before exercise

• During Exercise:

  • For longer workouts, consume carbohydrates and electrolytes to maintain energy and hydration

• Post-Exercise:

  • Consume carbohydrates and proteins to replenish energy stores and repair muscles

  • Aim to eat within 30 minutes of exercise

Key Takeaways:

• Proper nutrition is essential for optimal sports performance and overall health.

• Focus on a balanced diet that includes a variety of carbohydrates, proteins, fats, vitamins, and minerals.

• Stay hydrated by drinking plenty of water throughout the day, especially during and after exercise.

• Tailor your nutrition to your specific sport and training needs. Consult a registered dietitian or sports nutritionist for personalized advice.