Dog Structure: Definition, Purpose, and Problems
Definition: Dog’s body consists of bones, muscles, tendons and ligaments. These are used to support the whole body.
They make up the skeleton or frame of your dog. Your dog’s skeletal system is made up of bones (chondrocytes) which are composed mainly of cartilage (joints). The joints allow your dog to move their bodies. Joints are connected with tendons (muscles), ligaments (supporting tissues) and skin.
Purpose: Bones, muscles, tendons and ligaments are used to perform various functions such as walking, running, jumping and climbing. They are essential for all animals including humans.
Dogs have many bones that they use for different purposes like chewing food, fighting or even just playing. Some bones are larger than others making them stronger or smaller making them weaker.
Problems: There are several problems that occur when your dog has too much bone mass. Bone mass affects the joint structure causing pain and discomfort.
You may experience arthritis if there is excessive bone growth in the spine, pelvis or hip area. If your dog suffers from osteoarthritis it means that they suffer from degenerative changes in their joints. In other words, the cartilage wears away causing bones to rub together. This can result in limited mobility or complete immobility.
Your dog may also suffer from panosteitis, which is a long-term inflammation of the bone. The cause of this condition is not known but it affects large breed dogs.
Typically this condition is seen in growing dogs that are between 6 to 18 months old. Symptoms include fever, depression and loss of appetite. If your dog suffers from panosteitis they will exhibit a lameness in one or more of their legs. It is important to take your dog to the vet if you notice any of these symptoms.
Anatomical conformation is very important for dogs. It helps them to thrive and be comfortable in their own skin.
Having healthy bones, joints, tendons and ligaments help your dog to live a long and happy life.
Anatomical conformation: Definition, purpose and problems
The skeletal system is a part of a dog’s anatomy. It provides support and protects the body’s internal organs and allows movement.
Dogs have a total of 239 bones. 206 of these are called the Tetrapod (dwarf) Bones and consist of long bones, ribs, and some flat bones. In addition, there are a total of 28 floating bones called Symphysial (symphysis) which are located where the backbone and cranium join. In human anatomy, the skull consists of many small bones. In dogs, the skull is made up of two large bones covered by skin and fur on the outside and meninges on the inside.
Another important part of a dog’s skeletal system is its teeth. A dog has a total of 276 teeth which include canines, incisors, premolars and molars.
The purpose of these teeth is to tear, grab and chew food. Canines are used for ripping and gripping. Incisors are located in the front of the mouth and are used for cutting food. The premolars and molars are used for grinding food.
Bones provide protection, support and allow movement in the body. There are two types of skeletal systems in the body.
Endoskeleton and exoskeleton.
The endoskeleton is located inside the body and is usually connected to the skin and other organs. The exoskeleton is located on the outside of the body and protects the body.
There are several types of bones in a dog’s skeletal system. These are known as long bones, flat bones, irregular bones, sesamoid bones and skull bones.
Long bones are the longest bones in the body. They consist of a long cylindrical part called the diaphysis which has round projections called the epiphyses at either end.
Long bones include the radius, humerus, femur and tibia.
Flat bones are thin and flatter than long bones. They include the scapula and ribs.
Irregular bones consist of bones that do not fit into any other category. These bones include the vertebrae, patella, and mandible.
Sesamoid bones consist of two small bones that are embedded in a tendon such as the patella (kneecap).
Skull bones consist of the 14 cranial bones and the 32 facial bones. The cranial bones include the mandible, hyoid, sternebrae, occipital, frontal, lacrimal, nasal, palatine, zygomae, inferior horn of the innominate, maxilla, inferior horn of the maxilla, ipsilateral nasal and lateral nasal.
The facial bones include the vomer, superior horns of the innominate, nasal, lacrimal, zygomae, inferior horn of the maxilla, ipsilateral nasal, superior nasal conchae, inferior nasal conchae, superior labial and orbital and inferior labial and orbital.
The skeletal system provides several important functions. They include protection, support, movement, production of blood cells and red blood cells and endocrine regulation.
Skeletal anatomy consists of the axial skeleton and the appendicular skeleton. The axial skeleton consists of 80 bones and includes the skull, hyoid, ribs, vertebrae, and sternum.
The appendicular skeleton consists of 126 bones and includes the pectorial girdle and limbs. The bones of the limbs include the humerus, radius and ulna, carpals, metacarpals and phalanges.
“All of these bones came from a single bone as the creator spirit, Wandering Soul, was moulding the first man out of clay. The bone is called tukisin and is now an important part of the sacred bundle.” — Ojibwe myth
There are several types of tissue in the body including epithelial, connective, nervous, muscle, endocrine and neural tissue.
Epithelial tissue is one of the 4 main types of tissue. It consists of a layer of cells that cover surfaces or lines tubes in the body.
Connective tissue is one of the 4 main types of tissue. It serves to connect and support other tissues and organs in the body.
There are three subtypes including loose connective tissue, dense connective tissue and adipose tissue (fat).
Nervous tissue is one of the 4 main types of tissue. It consists of specialised cells that communicate electrical signals.
The tissue is sensitive and functions to receive, trigger and transmit electrochemical nerve impulses to the brain.
Muscle tissue is one of the 4 main types of tissue. It consists of specialised cells designed to contract and exert force.
Endocrine tissue is one of the 4 main types of tissue. It consists of specialised cells designed to secrete hormones directly into the blood.
The heart is a muscular organ that pumps blood around the body. It is divided into two distinct sides, the right and left sides, with each side taking a turn at pumping oxygenated blood throughout the body.
The brain is the control centre of the body. It controls and coordinates all movement and action.
It consists of four major parts, the medulla oblongata, pons, midbrain and cerebellum.
The digestive system is a series of organs working together to turn food into useful nutrients for the body. The digestive tract begins with the mouth and continues to the rectum.
Food is masticated by the teeth, soaked with saliva and then swallowed down the esophagus into the stomach. Here it is broken down with the help of hydrochloric acid and digestive enzymes. After leaving the stomach food is passed into the small intestine where most of the nutrients are absorbed. After this the remains of the food passes into the large intestine and here bacteria break down any remaining insoluble substances. The waste is then stored in the rectum before being excreted from the body.
The circulatory system is a series of organs working together to transport oxygen and nutrients to cells and transport waste away from them. The circulatory system consists of the heart, blood vessels and blood.
The skeletal system is a combination of bones linked by joints. It serves to protect inner organs and gives shape to the body.
The bones also store calcium and other minerals, giving rigidity and physical strength.
The muscular system is a combination of muscles that enable movement by exerting force upon the skeletal system. Without it we would not be able to move, let alone breathe or blink.
The reproductive system consists of genitals and the systems associated with them. It enables sexual reproduction and the creation of offspring.
The excretory system is a series of organs that remove waste from the blood. This system begins with the kidneys which filter poisonous wastes out of the blood.
These wastes are stored in the bladder until they are passed out of the body through the urethra.
The integumentary system is a series of organs that protect the body. It consists of two layers, the inner layer called the mucosa and the outer layer called the skin.
The skin has two functions, protection and sensation.
A cell is the fundamental unit of structure in all living things. It is a microscopic organelle responsible for carrying out basic biological functions in organisms.
In humans it is most commonly known as a skin cell.
A food chain describes the sequence of predation between different organisms. In a food web, there are many feeding connections between different organisms.
Each organism is dependent on another and each is prey to another.
The transfer of heat between objects is called thermal transfer. It occurs in two main ways, conduction and convection.
Conduction is when thermal energy moves from atom to atom in solids, liquids and gases. Convection is when the heat energy is transferred through the movement of fluids.
A pathway for fluid flow in the body is called a canal. These canals are fluid-filled tubes that connect and carry fluids around the body.
The main ones include the Eustachian tubes, the cochlea and the semicircular canals.
A structure that helps to move objects is called a mechanism. It can either be powered by muscles or energy sources like electricity.
Common examples include the lever, pulley and winch.
A tube-like anatomical structure is called a canal. It can be of variable size but is surrounded by bone on both sides.
Canals are used to contain tendons or nerves, examples include the auditory canal and the carpal tunnel.
An anatomical part of a bone is called a crest. A crest is a broad, thick, raised border of a bone.
They are located at the ends of long bones beside joints and are strengthened with more bone tissue.
The inner layer of the skin is called the dermis. It is tightly connected to the epidermis and is composed of different types of cells which aid in sensation and keep the skin protected.
The dermis contains hair follicles, sweat glands and sebaceous glands.
A bony protrusion that protects a muscle or other internal organ is called a crest. It is found on the inside of bones and is shaped like a ridge.
The distance from the upper tip of your nose to the bottom of your chin is called the length. The distance from the bottom of your chin to the top of your head is called the height.
The distance from the tip of your head to your feet is called the width.
The type of tissue that makes bone is called compact bone. It contains red bone marrow which produces blood cells.
The outer layer of bone is called cortical bone and it provides strength and support.
The bony ridge at the upper part of your eye sockets is called the brow bone or brow ridge. It provides structural support for the muscles above your eyes.
The peak of a roof is called the apex. The space under a curved surface like the top of your front teeth is called the cusp.
The lowest point on an object is called the foot. The highest point on an object is called the vertex.
A process is part of a bone that extends from the main part. An arm, leg or spine bone all have multiple processes like condyles, trochanters and spinous processes.
The thin white cords in your lungs are called the pulmonary veins. They connect the pulmonary artery to the heart.
The thick dark red arteries carry oxygenated blood away from the heart. There are multiple types, examples include the aorta and the femora.
The process of turning food into energy is called metabolism. Specifically, it involves breaking down nutrients so that your cells can use them.
Homeostasis is the ability to keep certain aspects of your body stable. It requires a series of checks and balances so that one variable doesn’t fluctuate too far in one direction.
The porous outer layer of a bone is called the periosteum. It contains small blood vessels that help to create new bone cells.
The spongy middle layer of a bone is called the trabecular bone. It contains mostly tiny spaces filled with bone cells.
Your skeleton provides rigidity and support for your entire body. It helps to protect your vital organs and gives shape to your body.
The large amount of nerve fibers that pass through the spinal cord is called the cauda equina. It consists of myelinated fibers, which are responsible for reflex actions.
The bundle of nerve fibers that pass through the spinal cord are called the dorsal roots. They carry sensory signals from our bodies to our brain.
The flexible middle layer of a bone is called the spongiosa. It consists of cancellous bone which is made of tiny spaces filled with bone cells.
The short, thick bones of the limbs are called the flat bones.Examples include the scapula and the ilium.
The long, thin bones of the limbs are called the tubular bones. Some examples include the humerus and radius.
A bone that forms a joint with another bone is called a joint or ginglymus. It allows movement between the bones it connects.
For example, the shoulder joint is called the humerus and the scapula.
The process of removing impurities from blood is called dialysis. It is most commonly done by a machine, but in some cases can be done by an organ such as the kidney.
Your bones are living tissue that are constantly changing and regenerating. The hard, white part of your bones is called the cortical bone.
The porous inner part is called cancellous bone.
The set of muscles that allow you to bend your arm is called the flexors. The set of muscles that allow you to straighten your arm is called the extensors.
The outer layer of your skin is called the epidermis. The deeper layer of your skin is called the dermis.
The part just below the dermis that contains connective tissue associated with hair and sweat glands is called the periderm.
The large, flat bones of your body are called the Sesamoids bones. Sometimes they are attached to a tendon or joint capsule.
They help to increase the leverage power of muscles.
The small bones in your middle ear are called ossicles. They help to transmit sound vibrations from the eardrum to the inner ear.
The ability to withstand temperatures is called thermotolerance. People who cannot tolerate heat can suffer from heat exhaustion or even death.
The process of detecting changes in your environment is called perception. This can be very difficult when you are in a new or stressful situation.
The flat, thin bones that form your skull are called the Placoid bones. They protect your brain and give it shape.
The smaller bones that join your skull to your spine are called the Exoskeletal bones.
The bony layer of your skin is called the Cortical Bone. The larger, more solid bones are called the Axial Bones.
Some common examples include the femur and the tibia.
When a baby is first born it has over 270 bones. Over time, as the child grows and the rest of the body catches up, it decreases in size to around 206.
The process of recognizing a sound after you hear it is called audition. You have two ears that collect difference sounds and send them to your brain.
The process of making judgments about what you see is called perception. You have two eyes, giving your brain a slightly different view of things so you can tell how far away something is.
Over time, the ends of your long bones become thicker and more spherical. This is called the epiphyseal plate, and it allows your bones to grow in length.
The framework of your body is made up of over 206 bones. Over half of these are in your hands and feet, which is why they’re often called the terminal, or end, bones.
The center of your eye is called the retina. Because its cells contain pigment, they can change light into chemical reactions.
The nerves from your eyes meet in a structure behind your brain called the optic chiasma.
The part of your eye that detects light is called the cornea. Behind that is the iris, which controls how much light enters your eye.
Next is the pupil, which focuses light onto the retina.
As you move through the world, your eyes are getting more information than they can process. Your brain only alerts you to changes in your vision, like a moving object.
Everything else is processed subconsciously.
The parts of your brain that deal with conscious sight are in the back and center. The areas that process subconscious vision are all over the place.
If someone shoots you in the stomach, but the bullet doesn’t hit anything important, then you’re likely to survive. If they shoot you through the head, it’s unlikely you’ll make it.
Your vital organs are all in the middle of your body, protected by your spine and rib cage. Your stomach and most importantly, your heart and liver are located in the upper center of your torso.
When you eat a piece of fruit, you can feel the squish of the soft flesh between your teeth. But when you chomp down on an apple, a crunching sound is heard.
This is because apples have a fibrous internal structure called parenchyma.
The process of breaking down food into energy is called metabolism. It occurs thanks to your body’s trillions of cells working together.
Your skin has three layers: the top, epidermis; the middle, dermis; and the bottom, subcutaneous. The subcutaneous layer is mostly made up of fat, which helps protect your vital organs.
If you get a cut on your skin, capillaries just beneath the dermis will begin to leak blood. They’ll do this every time you’re cut until they grow back, which can take a while.
Your nails and hair don’t grow from the skin itself, but from invaginations in it called keratinocytes.
The average human hair grows around a half inch every month. But you must keep in mind that your hair doesn’t really “grow” at all, it just stays the same length and new hair pushes the old out.
Sources & references used in this article:
The growing problem of obesity in dogs and cats by AJ German – The Journal of nutrition, 2006 – academic.oup.com
Some practical solutions to welfare problems in dog breeding by PD McGreevy, FW Nicholas – ANIMAL WELFARE-POTTERS BAR-, 1999 – terrierman.com
People’s perception of brachycephalic breeds and breed-related welfare problems in Germany by K Steinert, F Kuhne, M Kramer, H Hackbarth – Journal of Veterinary …, 2019 – Elsevier
Getting priorities straight: risk assessment and decision-making in the improvement of inherited disorders in pedigree dogs by LM Collins, L Asher, J Summers, P McGreevy – The Veterinary Journal, 2011 – Elsevier
Proposal for a new radiological index to determine skull conformation in the dog by DA Koch, T Wiestner, A Balli… – Schweizer Archiv …, 2012 – econtent.hogrefe.com
Common ocular problems of Shin Tzu dogs by RE Christmas – The Canadian Veterinary Journal, 1992 – ncbi.nlm.nih.gov