human systems and their work

MUSCULAR SYSTEM

The muscular system is responsible for the movement of the human body. Attached to the bones of the skeletal system are about 700 named muscles that make up roughly half of a persons body weight. Each of these muscles is a discrete organ constructed of skeletal muscle tissue, blood vessels, tendons, and nerves. Muscle tissue is also found inside of the heart, digestive organs, and blood vessels. In these organs, muscles serve to move substances throughout the body.
Functions of the muscular system
-The muscular system creates movement. The primary function of muscular system is to produce voluntary gross and fine movements.
-It protects the organs.
-The cardiac muscle pumps blood.
-Smooth muscle aids digestion.
-Smooth muscle ensures blood flow.

SKELETAL SYSTEM

-The human skeleton is the internal framework of the body. It is composed of around 300 bones at birth this total decreases to 206 bones by adulthood after some bones have fused together. The bone mass in the skeleton reaches maximum density around age 20.And is anatomically divided into two parts, the axial skeleton and the appendicular skeleton.
-The core of the skeleton is referred to as the axial skeleton. It consists of the following 80 bones.
-Skull: 22 bones
-Hyoid: 1 bone
-Vertebrae: 32 bones
-Ribs: 24 bones
-Sternum: 1 bone

-Attached to the axial skeleton is the appendicular skeleton, which consists of 126 bones.
-Pectoral girdle: 4 bones
(Scapula and clavicle)
-Arms and forearms: 6 bones
(Humerus and radius)
-Wrists and hands: 54 bones
(Carpals, metacarpals, and phalanges)
-Bony Pelvis: 2 bones (Os coxae)
-Thighs and legs: 8 bones
(Femur, patella, tibia, and fibula)
-Ankles and feet: 52 bones
(Tarsals, metatarsals, and phalanges)

FUNCTIONS OF SKELETAL SYSTEM

-Functionally, the bones primarily give support to the appendages and protect the fragile organs of the body such as the brain, spinal cord, heart, and lungs.
-They also store calcium and phosphorus in the hard bone matrix, which can be released when needed elsewhere.
-The bumps, ridges, and grooves on the surface of bones provide attachment sites for the skeletal muscles.
-Additionally, many bones contain a soft tissue called marrow that produces new blood cells and stores fat.

RESPIRATORY SYSTEM
Anatomy of the Respiratory System
-Nose and Nasal Cavity. The nose and nasal cavity form the main external opening for the respiratory system and are the first section of the bodys airwaythe respiratory tract through which air moves. …
-Mouth.
-Pharynx.
-Larynx.
-Trachea.
-Bronchi and Bronchioles.
-Lungs.
-Muscles of Respiration.
-It is part of the respiratory system and is located between the pharynx and the trachea. Humans use the larynx to breathe, talk, and swallow. Its outer wall of cartilage forms the area of the front of the neck referred to as the Adams apple. The vocal cords, two bands of muscle, form a V inside the larynx.

DIGESTIVE SYSTEM
-The digestive system is a group of organs working together to convert food into energy and basic nutrients to feed the entire body. Food passes through a long tube inside the body known as the alimentary canal or the gastrointestinal tract. The organs of digestive system are:
-Mouth.
-Throat.
-Esophagus.
-Stomach.
-Small Intestine.
-Colon (Large Intestine)
-Rectum.
-Anus.

FUNCTION OF DIGESTIVE SYSTEM
-The mouth is the beginning of the digestive tract. In fact, digestion starts here as soon as you take the first bite of a meal. Chewing breaks the food into pieces that are more easily digested, while saliva mixes with food to begin the process of breaking it down into a form your body can absorb and use.
-The liver has multiple functions, but its main function within the digestive system is to process the nutrients absorbed from the small intestine. Bile from the liver secreted into the small intestine also plays an important role in digesting fat. It breaks down and secretes many drugs. Gallbladder.

CIRCULATORY SYSTEM
-The circulatory system is centred on the HEART, a muscular organ that rhythmically pumps BLOOD around a complex network of BLOOD VESSELS extending to every part of the body. Blood carries the oxygen and nutrients needed to fuel the activities of the bodys tissues and organs, and it plays a vital role in removing the bodys waste products.

HEART
-The heart contracts tirelessly more than 2.5 billion times over an average lifetime to pump blood around the body. These contractions are triggered by electrical impulses that originate in a specialized area of heart tissue. The signals spread through the muscle in the wall of the heart via a network of conducting fibres.
-The heart has two upper chambers, called atria, and two lower chambers, called ventricles. Blood from the body arrives in the right atrium. This blood is low in oxygen, and is shown here in blue. The blood passes to the right ventricle, which pumps it to the lungs to pick up more oxygen. The left atrium receives oxygen-rich blood (red) back from the lungs. This passes to the left ventricle, which pumps it by way of the aorta to the body.
-At the exit of each heart chamber lies a valve, which ensures the one-way flow of blood through the heart and into the circulation. These valves are made of flaps that open to allow blood to pass through but snap tightly shut to prevent backflow. The valves have three flaps, except for the valve between the left atrium and left ventricle, which has two.

BLOOD VESSELS
-If an adults blood vessels were laid end to end, they would stretch out over 100,000 km (62,500 miles). There are three main types of vessel. Arteries carry blood from the heart to the bodys tissues, while veins carry blood back from the tissues to the heart. Small arteries are called arterioles and small veins are referred to as venules. The third and smallest type of vessel, capillaries, form a network connecting the smallest arterioles with the smallest venules.

EXCRETORY SYSTEM
-The excretory system is a collection of organs tasked with removing excess nitrogen and other toxins from the body. The kidneys, liver and large intestine perform most of the filtration duties. Solid waste passes out through the colon, gaseous waste exits the body through the lungs and excess liquid leaves through the bladder and skin