1. Introduction

The digestive system is responsible for the mechanical and chemical breakdown of food, absorption of nutrients, and elimination of waste.

Components: Oral cavity, Pharynx, Esophagus, Stomach, Small intestine,  Large intestine, Accessory organs (Salivary glands, Liver, Gallbladder,  Pancreas)

Functions:

Ingestion – taking in food

Propulsion – swallowing and peristalsis

1. Introduction

The lymphatic system is a network of vessels, nodes, and organs that returns interstitial fluid to blood, absorbs dietary fats, and participates in immune defense.

Functions:

Fluid balance: Returns 2–3 L interstitial fluid/day to circulation

Fat absorption: Via lacteals in small intestine

Immune surveillance: Filters pathogens via lymph nodes and spleen

1. Introduction

The endocrine system consists of glands that secrete hormones directly into the blood, regulating growth, metabolism, reproduction, and homeostasis.

Major glands: Hypothalamus, Pituitary, Thyroid, Parathyroid, Adrenal, Pancreas, Pineal, Gonads.

Hormone action: Endocrine (blood), Paracrine (local), Autocrine (self)

2. Hypothalamus and Pituitary

2.1 Hypothalamus Anatomy

1. Heart Anatomy – In-Depth

1.1 External Anatomy

• Located in the middle mediastinum, apex pointing to 5th intercostal space midclavicular line

• Surfaces:

  • Sternocostal: RA & RV predominantly

  • Diaphragmatic: LV and some RV

INTRODUCTION

The sensory system enables the body to perceive, interpret, and respond to changes in the internal and external environment. It consists of sensory receptors, neural pathways, and sensory centers in the brain.Sensations are classified into:1. Somatic (General) Senses – widely distributed across the body.2. Special Senses – localized in specialized organs.

SOMATIC (GENERAL) SENSES

Somatic senses arise from receptors in the skin, muscles, joints, and viscera. They provide information about touch, pressure, temperature, pain, and body position.

Introduction

The skin, together with its associated structures such as hair, nails, and glands, forms the Integumentary System. It is the largest organ system of the body and plays a vital role in protection, regulation, and sensation. For NHPC students, understanding the structure and functions of the skin is essential because many diseases, burns, infections, and injuries involve this system.

The skin is the first line of defense between the body and the outside world. It helps regulate temperature, prevents water loss, allows sensation, and even helps produce Vitamin D. On average, an adult’s skin covers about 1.5 to 2 square meters and weighs nearly 15% of total body weight.

[Diagram Placeholder: Cross-section of skin showing epidermis, dermis, and hypodermis]

Structure of the Skin

The skin has three main layers — each with special structures and functions:

Introduction

The muscular system is one of the most vital systems of the human body. It enables movement, posture, stability, and heat production. There are over 600 muscles in the body, making up about 40–50% of total body weight. Muscles not only help in voluntary motion such as walking or lifting but also perform involuntary activities like heart beating and intestinal movements.

For NHPC PCL General Medicine students, understanding the structure and function of the muscular system is crucial to explain common conditions like cramps, paralysis, muscle fatigue, and neuromuscular disorders.

[Diagram Placeholder: Overview of Muscular System showing skeletal, smooth, and cardiac muscles]

1. Classification of Muscles

Muscles are classified into three main types based on structure, location, and control mechanism.

Introduction

The skeletal system physiology focuses on the functioning of bones, joints, and supporting tissues that maintain posture, facilitate movement, protect vital organs, and serve as a storehouse for minerals like calcium and phosphorus. Bones are not lifeless structures — they are dynamic, living tissues that continuously remodel throughout life.

This chapter explains how bones grow, maintain themselves, adapt to mechanical stress, and repair damage. Understanding bone physiology helps NHPC students grasp the basis of orthopedic diseases, fractures, metabolic disorders, and calcium imbalance in clinical practice.

[Diagram Placeholder: Overview of skeletal physiology – growth, remodeling, repair, and mineral regulation]

1. Bone Growth and Development

Bone growth begins even before birth and continues until early adulthood. The process through which bones are formed is called ossification or osteogenesis.

Introduction

The skeletal system forms the framework of the human body. It provides support, protection, and shape, allowing the body to move and function properly. It also plays vital roles in blood cell formation, mineral storage, and leverage for movement. For NHPC students, understanding the skeletal system is essential for diagnosing fractures, joint disorders, and metabolic bone diseases.

The adult human skeleton consists of about 206 bones, connected by joints, ligaments, and cartilage. These bones are classified by shape and function. The skeletal system works together with the muscular system to produce movement, forming the musculoskeletal system.

[Diagram Placeholder: Overview of human skeleton showing axial and appendicular divisions]

Functions of the Skeletal System

1. Support: Provides a rigid framework that supports the body and maintains its shape.2. Protection: Protects vital organs – skull protects brain, ribs protect heart and lungs, vertebrae protect spinal cord.3. Movement: Acts as levers for muscles;…