Key Concepts in Human Anatomy and Physiology

Sagittal Plane

Divides the body into left and right sections.

Frontal (Coronal) Plane

Divides the body into anterior (front) and posterior (back) sections.

Transverse (Horizontal) Plane

Divides the body into superior (upper) and inferior (lower) sections.

Cellular Level

Basic unit of life, including various cell types.

Tissue Level

Groups of similar cells performing a specific function (e.g., epithelial, connective, muscle, nervous).

Organ Level

Structures composed of two or more tissue types working together (e.g., heart, lungs).

Organ System Level

Groups of organs that work together to perform complex functions (e.g., cardiovascular system).

Dorsal Body Cavity

Contains the cranial cavity (housing the brain) and the spinal cavity (housing the spinal cord).

Ventral Body Cavity

Contains the thoracic cavity (housing the lungs and heart) and the abdominopelvic cavity (housing digestive organs, reproductive organs, and urinary organs).

Anatomical Position

Refers to the body standing erect with the face forward, feet together, and arms hanging at the sides with palms facing forward.

Anatomy

The study of the body's structure.

Physiology

The study of how the body functions.

Midsagittal Plane

A vertical plane that divides the body into equal left and right halves.

Sagittal Plane

Any vertical plane parallel to the midline that divides the body into unequal left and right portions.

Horizontal Plane

Also known as the transverse plane, divides the body into superior (upper) and inferior (lower) portions.

Frontal Plane

A vertical plane at right angles to the midsagittal plane that divides the body into anterior (front) and posterior (back) portions.

Basic Components of a Cell

Include the cell membrane, nucleus, cytoplasm, and chromosomes.

Role of the Nucleus

Contains genetic codes that are essential for the functioning and reproduction of the cell.

Role of the Cytoplasm

Comprises all the substance of a cell except the nucleus.

Chromosomes

Found in the nucleus and contain DNA.

Homeostasis

The harmony maintained by cells, tissues, organs, and systems working together in the body.

Differentiation

The term for the specialized function of cells.

Stem Cells

Immature, unspecialized cells in the body that can be induced to become other types of cells.

Embryonic Stem Cells

Come from embryos developed from fertilized eggs used for research.

Adult Stem Cells

Found in the tissues of both adults and children.

Formation of Tissues

Tissues are formed when many millions of the same type of cell join together to perform a specific function for the body.

Main Types of Tissues

The four main types of tissues in the human body are epithelial, connective, muscle, and nerve tissue.

Epithelial tissue

The primary functions of epithelial tissue are to provide protection, produce secretions, and regulate the passage of materials across them.

Connective tissue

Connective tissue serves as the major support material of the body, providing support and connecting organs and tissues.

Muscle tissue

Muscle tissue has the ability to lengthen and shorten, allowing for the movement of body parts. Skeletal muscles can be classified as either voluntary or involuntary.

Nerve tissue

Nerve tissue is found in the brain, spinal cord, and nerves. Its primary function is to coordinate and control many body activities.

Organ

An organ is defined as a structure formed when several types of tissue group together to perform a single function, such as the stomach, which contains all four tissue types and performs digestive functions.

Body system

A body system is composed of a group of organs that work together to perform a major function to keep the body healthy and functional.

Dorsal Cavity

The dorsal cavity contains the spinal canal, which contains the spinal cord, and the cranial cavity, which contains the brain.

Thoracic Cavity

The thoracic cavity contains the lungs, heart, and accessory parts for their functioning.

Abdominal Cavity

The abdominal cavity includes most of the digestive tract and supporting organs for digestion.

Pelvic Cavity

The pelvic cavity contains the urinary bladder, rectum, and reproductive system.

Body systems

Body systems consist of specific organs and serve specific purposes essential for maintaining homeostasis and overall health.

Axial skeleton

The axial skeleton consists of 80 bones and its primary function is to protect the major organs of the nervous, respiratory, and circulatory systems.

Appendicular skeleton

The appendicular skeleton consists of 126 bones and includes the upper extremities (shoulders, arms, hands) and lower extremities (hips, legs, feet).

Bone tissue

Bone tissue, or osseous tissue, is composed of connective tissue that includes an organic component (cells and matrix) and an inorganic component (minerals).

Minerals in bone structure

Minerals, primarily calcium and phosphate, give rigidity to bone and act as reservoirs to maintain essential blood mineral concentrations when the body's supply is inadequate.

Skull

The skull consists of 28 bones.

Main components of the axial skeleton

The main components of the axial skeleton are the skull, spinal column, ribs, and sternum.

Function of appendicular skeleton

The function of the appendicular skeleton is to protect the organs of digestion and reproduction.

Three layers of bone

Periosteum – the dense, tough outer shell that contains blood vessels and nerves. Compact or dense tissue – the hard, smooth layer that protects the tissue within. Spongy or cancellous tissue – the porous, honeycombed material found inside most bones, which allows the bone to be strong yet lightweight.

Appendicular Skeleton

Consists of the bones of the limbs and the girdles that attach them to the axial skeleton.

Periosteum

A thin layer of connective tissue containing nerves and blood vessels, with an inner layer of loose connective tissue that has osteoblasts.

Compact Bone

The strong and hard section of the bone, dense and forming the main shaft of long bones and the outer layer of other bones.

Cancellous Bone and Marrow

Found inside the bone, lighter in weight and not as strong as compact bone, with marrow that produces blood cells.

Function of Periosteum

Serves as a protective layer and contains nerves and blood vessels; has an inner layer of loose connective tissue that contains osteoblasts, essential for bone growth and repair.

Sharpey's Fibers

Fibers that anchor the periosteum to the bone.

Difference between Compact and Cancellous Bone

Compact bone is dense, strong, and forms the main shaft of long bones and the outer layer of other bones, while cancellous bone is lighter in weight, found inside the bone, and is not as strong.

Role of Bone Marrow

Produces white blood cells (fight infection), red blood cells (carry oxygen), and platelets (help stop bleeding).

Fibrous Joints

Joints that do not move, such as the sutures of the skull.

Cartilaginous Joints

Joints made of connective tissue and cartilage that move only slightly, like the joints between the vertebrae.

Synovial Joints

Movable joints that account for most joints in the body and may be lined with a bursa filled with synovial fluid for cushioning.

Function of Bursa

Acts as a cushion to ease movement by reducing friction between the moving parts of the joint.

Difference between Fibrous and Cartilaginous Joints

Fibrous joints do not move at all, while cartilaginous joints allow for very slight movement.

Ball-and-Socket Joints

A type of synovial joint that allows for a wide range of movements, including flexion, extension, and rotational movements.

Hinge Joints

Allow movement in only one direction, similar to the hinge on a door.

Gliding Joints

Allow the bones to slide over one another, facilitating a range of movements.

Pivot Joint

Found at the base of the skull and allows the head to rotate.

Saddle Joint

Allows movements such as touching the thumb to the fingers.

Gomphoses

Specialized joints that allow only very slight movement, such as attaching a tooth to the socket.

Percentage of Body Weight by Muscular System

The muscular system makes up 30 to 40 percent of total body weight.

Types of Muscles

The three types of muscles identified are striated, smooth, and cardiac.

Function of Striated Muscles

Provide for external body movement, such as facial expressions and activities like bike riding.

Voluntary Muscles

Striated muscles that are under conscious control.

Characteristics of Smooth Muscle Tissue

Non-striated tissue that is involuntary, controlled by the autonomic nervous system and not consciously controlled.

Locations of Smooth Muscle

Found in internal organs (except the heart), blood vessels, skin, and ducts from glands.

Smooth muscle

Characterized as nonstriated tissue and is involuntary, meaning it is controlled by the autonomic nervous system and not consciously controlled.

Cardiac muscle

Has a striated appearance like skeletal muscle but is involuntary in action and is only found in the heart.

Muscle contraction

The tightening of a muscle, making it shorter and thicker.

Muscle relaxation

The return to its original form or shape.

Muscle origin

Refers to the place where the muscle begins, which is the more fixed attachment toward the midline of the body.

Muscle insertion

The place where the muscle ends, referring to the more movable attachment that is away from the midline of the body.

Cardiovascular system

Consists of the circulatory system, heart, and lymphatic system.

Primary function of the cardiovascular system

To provide life-sustaining functions for the survival of bodily cells and tissues.

Disorders of the cardiovascular system

Include those affecting the heart and lymphatic system, which have specific signs and symptoms.

Functions of the circulatory system

1. Transports oxygen and nutrients to body cells, carbon dioxide and waste products from body cells, hormones and antibodies throughout the body. 2. Regulates body temperature and maintains chemical stability.

Function of the heart in the circulatory system

Acts as a pump that circulates blood throughout the body.

Layers covering the heart

1. Pericardium: Outer layer composed of a double-walled sac. 2. Myocardium: Tough muscular wall.

Function of the heart's right side

Pumps blood to the lungs.

Types of chambers in the heart

The atria, which receive blood, and the ventricles, which pump blood.

Role of one-way valves in the heart

Prevent the backflow of blood and separate the chambers of the heart by opening and closing with each heartbeat.

Tricuspid valve

Located between the right atrium and the right ventricle and has three cusps.

Mitral valve

Lies between the left atrium and the left ventricle and has two cusps.

Functions of the pulmonary and aortic semilunar valves

The pulmonary semilunar valve allows blood to flow from the right ventricle into the pulmonary artery, while the aortic semilunar valve allows blood to flow from the left ventricle into the aorta.

Blood flow through the heart

1. Blood enters the right atrium from the superior and inferior venae cavae. 2. It flows into the right ventricle. 3. The right ventricle pumps blood into the pulmonary artery to the lungs. 4. Oxygenated blood returns to the left atrium via the four pulmonary veins. 5. Blood flows from the left atrium into the left ventricle. 6. The left ventricle pumps blood into the aorta, distributing it to the body (except the lungs).

Major types of blood vessels

1. Arteries 2. Veins 3. Capillaries.

Functions of blood

1. Transportation of nutrients, gases, waste products, and hormones.

Regulation

The process of maintaining body fluids, pH balance, and body temperature.

Protection

The mechanism that defends against pathogens and prevents blood loss after injury through clotting.

Erythrocytes

Red blood cells that contain hemoglobin, which allows them to carry oxygen.

Leukocytes

White blood cells that protect the body from infection and disease.

Plasma

A straw-colored fluid that transports nutrients, hormones, and waste products; it is 91% water and 9% plasma proteins, including albumin and globulin.

Arteries

Large blood vessels that carry blood away from the heart to all regions of the body, having thicker, more elastic walls to withstand high pressure.

Veins

Blood vessels that form a low-pressure collecting system that returns waste-filled blood to the heart, having thinner walls compared to arteries and being less elastic.

Capillaries

Microscopic vessels that connect the arterial and venous systems, allowing for the exchange of nutrients and waste between blood and tissues.