Title: Chapter 1: The Human Body

[Image: Chapter 1: The Human Body]

Learning Objectives

After studying this chapter, you should be able to:

1. Define the anatomic terms used to refer to the body in terms of directions and geometric planes. 📐👤
2. Describe the major cavities of the body and the organs they contain. 🏠🫀 Explain what a cell is. 🔬🧬
3. Describe the major functions of the four types of human tissue. 🧠🦴
4. List the major systems of the body, the organs they contain, and the functions of those systems. 🏃‍♂️🫁
5. Define the terms anatomy and physiology. 🦵🧠
6. Define homeostasis. ⚖️🌡️

Key Terms

Introduction

🧠 The Fascinating Study of the Human Body

From ancient times, humans have been curious about the body’s functions, especially when faced with illness and death. Early cultures relied on healers who 🌿 used plants and herbs, alongside spiritual rituals, to restore health.

As societies and science evolved, so did our knowledge of the human body. 🔬 Key figures such as:

- Leonardo da Vinci 🖌️
- Andreas Vesalius 📖
- William Harvey ❤️

Key Figures

Leonardo da Vinci 🖌️ – first to accurately illustrate the human skeleton.

Andreas Vesalius 📖 – author of influential works on human anatomy.

William Harvey ❤️ – discovered the circulation of blood.

Today, the fields of:

- 🏗️ Anatomy – exploring the structure of the body.
- ⚙️ Physiology – understanding how body parts function together.

are closely intertwined, helping us grasp how different organs work together. For example, the mouth's teeth, tongue, and salivary glands all play a role in digestion! 🍽️

Additionally, pathology 🦠, the study of diseases, continues to reveal new insights into the human body. Even today, scientists are still discovering the mysteries of how this complex system operates. 🔍

Below is the summary breakdown of what we have covered!

Terms of Direction

Brief Overview

In this chapter, you will be introduced to the essential directional terms 🧭 used to describe the location of body parts in relation to the human body as a whole. These terms are fundamental to understanding anatomy and serve as a universal language 🌐 for precise communication.

Key concepts you will explore include:

- Superior ⬆️ (above) and Inferior ⬇️ (below):
Example: The head is superior to the neck; the foot is inferior to the ankle.
- Anterior 👉 (front) and Posterior 👈 (back):
Example: The mammary glands are on the anterior chest wall; the vertebral column is posterior to the digestive tract.
- Medial ➡️ (toward the midline) and Lateral ⬅️ (away from the midline):
Example: The nose is in a medial position on the face; the ears are in a lateral position.
- Proximal and Distal:
Example: The elbow is proximal to the wrist; the wrist is distal to the elbow.

These concepts are crucial for studying and communicating the relationships between body structures in both medical 🏥 and anatomical contexts. Figures 📊, such as the anterior and lateral views of the body, will further aid in visualizing 👁️ these terms and solidifying your understanding.

📹Watch the video

In this subchapter, you will find a video 📹 that explains the anatomical directional terms, used to reference specific points or areas of the human body. Watch the video and focus on these key points:

1. How directional terms are used to describe body positions.
2. The importance of these terms in anatomical communication.
3. Practical examples of how to apply terms like superior, inferior, anterior, and more.

Anatomical Position And Directional Terms Video

In this video we discuss the anatomical directional terms, which is a directional language used to reference points or areas of the human body. Watch and answer the questions until the end of the video

What describes the anatomical position?

Q: 1. What describes the anatomical position?
- Lying down with arms above the head (Incorrect!)
- Standing erect, face forward, arms at the sides (correct) (You are correct! Good job!) (if not chosen: Try better next time!)
- Sitting with legs crossed
- Squatting with hands on knees

Which of the following pairs describes the terms "anterior" and "posterior"?

Q: Which of the following pairs describes the terms "anterior" and "posterior"?
- Front and back (correct)
- Upper and lower
- Side and center
- Close and further

When describing the body, __ means toward the midline, while lateral means away from the midline.

Fill in the missing words

Q: When describing the body, [...]  means toward the midline, while lateral means away from the midline.
A: medial

Superficial means closer to the surface of the body.

Q: Superficial means closer to the surface of the body.
A: true

Choose the correct statement.

📘✨Explore & Apply

In the study of human anatomy, precise communication is essential, especially when describing the locations and relationships of different body parts. Anatomists use directional terms to reference specific areas of the body in relation to others. These terms provide a standardized way to describe the position of structures, which is crucial in fields such as medicine, biology, and physical therapy. 🩺💡

This lesson will guide you through the most important directional terms used in anatomy, such as superior, inferior, anterior, posterior, medial, lateral, proximal, and distal. You will learn how these terms relate to different body parts and their functions. Plus, you’ll get hands-on with interactive activities designed to make these concepts stick! 🎯💻

By completing this lesson, you will be able to:

- 📝 Describe the relative positions of body parts using directional terms.
- 📍 Identify and label various anatomical positions and regions.
- 🚀 Apply directional terminology in practical scenarios, boosting your anatomical vocabulary and comprehension.

Let’s dive in and explore these key terms! 💪 As you work through the interactive activities, keep in mind how each term helps create a clear picture of the body as a whole.

Directional Terms Definition

Title

[Image: TItle]

Superior

[Image: 2]

Inferior

[Image: 3]

Anterior

[Image: 4]

Posterior

[Image: 5]

Cephalad

[Image: 6]

Medial

[Image: 7]

Lateral

[Image: 8]

Proximal

[Image: 9]

Distal

[Image: 10]

Activity: Label the terms of direction to the correct parts of the body.

- Anterior View
- Lateral View
- Superior
- Inferior
- Medial
- Proximal
- Distal
Q: Lateral View
A: Lateral View
Q: Superior
A: Superior
Q: Inferior
A: Inferior
Q: Medial
A: Medial
Q: Proximal
A: Proximal
Q: Distal
A: Distal
Q: Anterior View
A: Anterior View

Planes

In this section, you'll learn about the planes used to divide the body for anatomical study:

- Midsagittal (Median) Plane 📏
- Sagittal Plane 🎯
- Horizontal (Transverse) Plane ➗
- Frontal (Coronal) Plane 🛑
- Longitudinal Section 🔄
- Transverse (Cross) Section ✂️

These planes help describe how the body is sectioned for medical imaging and dissection.

📹Watch the video

In this subchapter, you will find a video 📹 that explains the planes of the body, which are used to describe how the body is sectioned or divided. Watch the video and focus on these key points:

1. What are body planes?
2. Sagittal planes
3. Coronal (frontal) planes
4. Transverse planes
5. Oblique planes

Body Planes - Planes Of The Body - Sagittal Planes, Transverse Planes And Frontal Planes

Instruction: Watch and answer all the questions in the video until the end.

What is a body plane?

Q: What is a body plane?
- A physical object
- An imaginary flat surface (correct)
- A type of exercise
- A medical instrument

How many major body planes are mentioned in the video?

Q: How many major body planes are mentioned in the video?
- One
- Two
- Three (correct)
- Four

What do transverse planes divide the body into?

Q: What do transverse planes divide the body into?
- Left and right sections
- Upper and lower sections (correct)
- Anterior and posterior sections
- Equal halves

Which plane runs from side to side and top to bottom?

Q: Which plane runs from side to side and top to bottom?
- Sagittal plane
- Transverse plane
- Coronal or frontal plane (correct)
- Oblique plane

Transverse planes

Fill in the missing words

Q: Transverse planes divide the body into [...] and [...] sections.
A: upper; lower

The number of possible body planes

Choose the correct statement on the number of possible body planes

- There is an infinite number of body planes. (correct)
- There are a limited number of body planes.
- Only three body planes exist.
- Oblique planes are the only additional planes available.

Summary

Choose the correct statement related to body planes:

- Sagittal planes divide the body into left and right sections, while coronal planes separate the body into anterior and posterior sections. (correct)
- A body plane is a solid structure used in medical procedures.
- There are five major body planes that are universally accepted in anatomy.
- Transverse planes only divide the body into equal upper and lower sections.

Watch back this section of the video

📘✨Explore & Apply

Occasionally, it is useful to describe the body as having imaginary flat geometric surfaces passing through it called planes (Figure 4.1). These terms are most useful when describing dissections to look inside an organ or the body as a whole.

Instruction: Click on the hotspot to discover the description of dissections.

Planes Hotspot

Plane vertically dividing the body into equal right and left portions

Any plane parallel to the midsagittal or median plane vertically dividing the body into unequal left and right portions

A horizontal or transverse plane is any plane dividing the body into superior and inferior portions.

Frontal or Coronal plane is one that divides the anterior (or ventral) and posterior (or dorsal) portions of the body at right angles to the sagittal plane.

Figure 4.1:  The planes of the body illustration

Activity:

Drag the Words: Planes of the Body

Drag the words into the correct boxes

Q: Occasionally, it is useful to describe the body as having imaginary flat geometric surfaces passing through it called [...]. These terms are most useful when describing dissections to look inside an organ or the body as a whole. A [...] plane vertically divides the body through the midline into two equal left and right portions or halves. This is also referred to as a [...] plane. A [...] plane is any plane parallel to the midsagittal or median plane vertically dividing the body into unequal right and left portions.

A [...] plane is any plane dividing the body into superior and inferior portions. A [...] or [...] plane divides the anterior (ventral) and posterior (dorsal) portions of the body at right angles to the sagittal plane. When organs are sectioned to reveal internal structures, two other terms are often used. A cut through the long axis of an organ is called a [...] section, and a cut at right angles to the long axis is referred to as a [...] or [...] section.
A: planes; midsagittal; median; sagittal; transverse; frontal; coronal; longitudinal; cross; transverse

Cavities

In this section, you will explore the body cavities 🏺, which house and protect various organs. These cavities are essential for understanding the organization of the body's internal environment. The key concepts you'll encounter include:

1. Dorsal Cavity 🧠
2. Ventral Cavity ❤️
3. Parietal vs. Visceral 🩻

Understanding these cavities and their subdivisions is crucial for visualizing how the body's organs are arranged and protected within the internal environment. Figures 📊, such as diagrams of the dorsal and ventral cavities, will assist in clarifying these structures.

📹Watch the video

In this subchapter, you will find a video 📹 that explains the major body cavities, which house and protect vital internal organs. Watch the video and focus on these key points:

- The two segmented body cavities: ventral and dorsal.
- The dorsal cavities: including the cranial and spinal cavities, which protect the brain and spinal cord.
- The ventral cavities: consisting of the thoracic and abdominopelvic cavities, separated by the diaphragm.
- The thoracic cavity: divided into the mediastinum, which contains the heart and major structures, and the pleural cavities, which house the lungs.
- The abdominopelvic cavity: subdivided into the abdominal cavity (containing digestive organs) and the pelvic cavity (containing reproductive organs and part of the large intestine).

These key points will help you understand the organization of body cavities and the organs they protect.

Body Cavities - Body Cavity Anatomy - Major Body Cavities

Instructions: Watch and answer the questions in the video. Submit all your answers at the end of the video.

What are the two main types of body cavities mentioned?

Q: What are the two main types of body cavities mentioned?
- Ventral and dorsal (correct)
- Cranial and spinal
- Thoracic and abdominopelvic
- Abdominal and pelvic

What is housed in the mediastinum?

Q: What is housed in the mediastinum?
- Lungs
- Spinal cord
- Heart, trachea, and major blood vessels (correct)
- Liver and gallbladder

Stomach is housed in the abdominal cavity

Q: Stomach is housed in the abdominal cavity.
A: true
If wrong: Stomach, liver and pancreas are housed in abdominal cavity.

The pelvic cavity includes...

The pelvic cavity includes

Fill in the missing words. The answer is not more than two words.

Q: The pelvic cavity includes the [...].
A: reproductive ograns

Summary of Body Cavities

Choose the correct statement.

- The body has several cavities that house internal organs, which can be categorized into ventral and dorsal cavities. (correct)
- The thoracic cavity contains the bladder and reproductive organs.
- The cranial cavity houses the lungs.
- The abdominopelvic cavity is located entirely in the dorsal region of the body.

📘✨Explore & Apply

The body has two major cavities: the dorsal cavity 🧠 and the ventral cavity ❤️ (Figure 5.1). Each of these is further subdivided into smaller cavities. The organs within any cavity are referred to as the viscera 🏥 (VISS-er-ah).

Explore the major cavities of the body and their subdivisions 🧠❤️ to understand how they protect and house vital organs within the dorsal and ventral sections.

Cavities Flash Cards

Types of Cavities

Q: Dorsal Cavity
A: Contains the cranial cavity (brain) and spinal cavity (spinal cord), located toward the back of the body.

Q: Ventral Cavity
A: Contains the thoracic cavity and abdominopelvic cavity, located toward the front of the body.

Q: Thoracic Cavity
A: The upper part of the ventral cavity, containing the heart, lungs, and other structures. It is divided into the mediastinum and pleural cavities.

Q: Abdominopelvic Cavity
A: The lower part of the ventral cavity, containing the abdominal organs (stomach, liver, intestines) and pelvic organs (bladder, reproductive organs).

Q: Mediastinum
A: The central part of the thoracic cavity, containing the heart, thymus, trachea, and major blood vessels.

Q: Pleural Cavities
A: The cavities located on either side of the mediastinum, each housing a lung.

Q: Cranial Cavity
A: The part of the dorsal cavity that houses the brain, located within the skull.

Q: Spinal Cavity
A: The part of the dorsal cavity that houses the spinal cord, located within the vertebral column.

Q: Diaphragm
A: A dome-shaped muscle that separates the thoracic cavity from the abdominopelvic cavity and aids in respiration.

Structural Units

In this section, you'll learn about the organization of living material:

- Cells 🧬
- Tissues 🧫
- Organs 🫀
- Body Systems 🧑‍⚕️
- Protoplasm 🌊
- Cell Membrane 🧱
- Organelles ⚙️

These components work together, forming the building blocks of life and organizing the body’s complex systems.

📹Watch the video

In this subchapter, you will find a video 📹 that explains the structural organization of the human body, detailing how the body is organized from the smallest units to complex systems. Watch the video and focus on these key points:

- The cellular level 🧬
- The tissue level 🧫
- The organ system level 🫀

This will help you comprehend the hierarchical organization of the human body, from simple to complex structures.

Structural Units

Watch the video and complete all of the questions until the end of the video. Submit your result at the end of the video.

What is the smallest unit of a pure substance or element?

Q: What is the smallest unit of a pure substance or element?
- Molecule
- Atom (correct)
- Cell
- Tissue

At which level do similar cells form body tissue?

Q: At which level do similar cells form body tissue?
- Organ level
- Organism level
- Cellular level
- Tissue level (correct)

Muscular and endocrine system

Mark the correct word in each paragraph.

The muscular system includes various components that help in movement and maintaining posture. However, bones /tendons /skeletal muscles are not part of the muscular system, as they belong to the skeletal system.

The endocrine system is responsible for hormone production and regulation. The pituitarygland /thymus /spleen is part of the endocrine system.
A: bones; pituitarygland

System involved in the production of gametes in males

Q: Urinary system is involved in the production of gametes in males.
A: false
If right: Correct. Reproductive system is involved in the production of gametes in males.
If wrong: Try Again

Summary of Structural Units

Choose the correct statement.

- Two or more different tissues combine to form an organ. (correct)
- The chemical level is the highest level of organization in the human body.
- The muscular system includes the heart and blood vessels.
- Organ systems do not interact with one another in the human body.

Rewatch the section in order to answer correctly.

📘✨Explore & Apply

All living material 🌱 is composed of cells 🔬, the smallest units of life. These cells are organized into tissues 🧫, which then form organs 🫁 that make up the major systems of the body 🧠.

- The cell is the basic unit 🧩 of biological organization.
- The liquid part of a cell is called protoplasm 💧 (PRO-toh-plazm), which is surrounded by a cell membrane 🧪 (also known as the plasma membrane).
- The cell membrane acts like a gatekeeper 🚪, selectively determining what can enter or exit the cell.

Inside the cell, protoplasm is an aqueous (watery) 💦, colloidal solution that contains proteins, lipids, carbohydrates, and inorganic salts 🧬. These components form specific structures within the cell called organelles ⚙️, which perform vital functions for cell survival.

Activity 1

A system is a group of organs working together to perform vital functions 🧠❤️. Now, let's explore the different types of organ systems in our body 🏃‍♂️ and discover how each contributes to keeping us healthy and functioning 🌟.

Figure 6.1

Intergumentary

The integumentary system is made up of two layers: the epidermis and the dermis. It includes the skin, hair, nails, sebaceous glands, and sweat glands. Its functions include insulation of the body, protection of the body from environmental hazards such as the ultraviolet radiation of the sun and certain chemicals, and regulation of body temperature and water. It also has receptor sites to detect changes in temperature and pressure.

Skeletal System

The skeletal system is composed of bones, cartilage, and the membranous structures associated with bones. It protects the soft and vital parts of the body and provides support for body tissues. Its bones act as levers for movement. This system also manufactures blood cells in red bone marrow and stores fat in yellow bone marrow. Bones store mineral salts like calcium and phosphorous.

Muscular System

The skeletal system is composed of bones, cartilage, and the membranous structures associated with bones. It protects the soft and vital parts of the body and provides support for body tissues. Its bones act as levers for movement. This system also manufactures blood cells in red bone marrow and stores fat in yellow bone marrow. Bones store mineral salts like calcium and phosphorous.

Figure 6.2

Nervous System

The nervous system consists of the brain, spinal cord, cranial nerves, peripheral nerves, and the sensory and motor structures of the body. Its functions include controlling, correlating, and regulating the other systems of the body; interpreting stimuli from the outside world; and controlling the special senses of sight, hearing, taste, and smell.

Endocrine System

The endocrine system consists of the endocrine (ductless) glands. The master gland, or pituitary, controls the other glands—thyroid, adrenal glands, ovaries, and testes. These glands produce hormones that chemically regulate the body’s functions. This system works with the nervous system through the hypothalamus of the brain, which controls the pituitary gland.

Cardiovascular System

The cardiovascular system, or blood circulatory, consists of the heart, arteries, veins, and capillaries. Its function is to pump and distribute blood, which carries oxygen, nutrients, and wastes to and from the cells of the body.

Looking at the next few organs system, explore and complete the information in order to understand better.

Activity 2

Activity 2B:Structural Units

Fill in the missing words

Q: The [...] system is made up of two kidneys, two ureters, the bladder, and the urethra. Its functions include the chemical regulation of the blood, the formation and elimination of [...], and the maintenance of [...].

The [...] system consists of the ovaries, uterine tubes, uterus, and vagina in females, and the testes, vas deferens, seminal vesicles, prostate gland, penis, and the urethra in males. Its functions include the maintenance of [...] characteristics and the perpetuation of our species.
A: urinary; urine; homeostasis; reproductive; sexual

Activity 3:

Instructions: Now, try out the game map after reading and exploring the organ systems. Complete the challenges to test your knowledge and master the systems that keep the body functioning!

Homeostasis​

In this section, you will explore the concept of homeostasis 🛠️, which is essential for maintaining the body’s internal balance. This process ensures that the body’s environment remains stable within narrow limits, allowing it to function properly. The key concepts you'll encounter include:

- Blood glucose regulation 🍞
- Body temperature control 🌡️
- Negative vs. Positive feedback loops 🔄

Understanding how the body maintains homeostasis is crucial for grasping how various organ systems work together to keep us healthy. Figures 📊, such as diagrams of feedback loops, will help clarify how the body responds to internal and external changes.

📹Watch the video

In this subchapter, you will find a video 📹 that explains the concept of homeostasis 🛠️, which refers to maintaining a stable internal environment within the body. Watch the video and focus on these key points:

- Definition of homeostasis 📚
- Sensing changes 👀
- Brain’s role 🧠
- Importance 💪

What is Homeostasis?

Instructions: Watch and answer all the questions in the video. Remember to submit your results at the end of the video.

What does homeostasis mean?

Q: What does homeostasis mean?
- Maintaining a constant internal environment (correct)
- The process of breathing
- The ability to move
- A type of cellular division

Q: What does the brain use to keep the body's internal environment stable?
- Hormones and nerves (correct)
- Muscles and bones
- Blood and oxygen
- Water and sugar

Why is homeostasis important for metabolism

Fill in the missing words

Q: Homeostasis is important for [...] because it controls the [...] in the body, ensuring stable conditions for all necessary processes.
A: metabolism; chemical reactions

Enzymes Change

Q: If the conditions for enzymes change, they may stop working.
A: true

Summary of homeostasis

Choose the correct statement.

- Homeostasis refers to the body's ability to maintain a constant internal environment. (correct)
- The pancreas releases glucagon when blood sugar levels increase.
- Homeostasis is not important for enzyme function in the body.
- The human body needs to maintain a temperature of 40 degrees Celsius for proper functioning.

📘✨Explore & Apply

Homeostasis (hom-ee-oh-STAY-sis) is the maintenance 🛠️ of the body’s internal environment within narrow limits. One of the first scientists to discuss its importance was Claude Bernard (1813–1878) 🧑‍🔬. Homeostasis is vital for survival 🌱, as many of the body’s systems work together to maintain balance. Examples of homeostasis include blood sugar levels, body temperature 🌡️, heart rate, and the fluid environment of cells. When homeostasis is maintained, the body remains healthy 💪—which is why your doctor checks your temperature and blood pressure during routine exams 🩺.

Let's look at two examples of maintaining homeostasis:

two examples of maintaining homeostasis

Example of maintaining homeostasis

[Image: Blood Glucose]

Example of maintaining homeostasis

[Image: Blood temperature]

The body constantly monitors itself to maintain homeostasis 🛠️, adjusting internal conditions when necessary. It uses a mechanism called the negative feedback loop 🔄 to correct any major deviations from the body’s normal state.

For example, the relationship between your thermostat and furnace works like a negative feedback loop:

- When the temperature in your home drops below 72°F 🥶, the furnace turns on to raise the temperature.
- When the temperature rises above 72°F 🔥, the thermostat turns off the furnace to prevent overheating.

Positive feedback ➕, on the other hand, increases the body’s response to a stimulus. A classic example is labor 🤰, where the uterus contracts with greater strength and frequency after the first contraction, helping with childbirth. Look at the negative feedback diagram below.

Homeostasis

Drag the words into the correct boxes

Q: Our [...] systems help control the internal environment of the body and cells so that it remains fairly constant. The [...], [...], [...], and [...] systems work together to ensure that every cell receives the right amount of oxygen and nutrients, and that waste products are eliminated quickly. If [...] is not maintained, the body will experience disease and, eventually, death.
A: organ; digestive; urinary; circulatory; respiratory; homeostasis