The Human Body – A Masterpiece of Nature
The human body is a miracle of evolution, made up of billions of cells, organs, tissues and systems all working together in harmony. From the complex control of the brain to the finely tuned movements of muscles, each element plays a role in maintaining the body's homeostasis (internal balance). In this comprehensive overview, we take a look at the body's major systems and their importance to our health and well-being.
1. The nervous system – the control center of the body
The nervous system is the body's communication network. It controls both conscious and unconscious processes and ensures that all systems work together smoothly.
structure of the nervous system
Central nervous system (CNS): Consists of the brain and spinal cord. The brain processes information and makes decisions, while the spinal cord serves as a highway for information between the brain and the body.
Peripheral nervous system (PNS): Transmits information between the central nervous system and the muscles, organs and sensory organs.
function of the nervous system
Motor control: Moves muscles and controls movements.
Sensory perception: Processes sensory stimuli (sight, hearing, touch, taste, smell).
Regulation of homeostasis: Regulates unconscious functions such as heartbeat, digestion and breathing.
Scientific knowledge
The nervous system works with electrical impulses that travel at speeds of up to 120 m/s (432 km/h).
The brain has about 86 billion neurons that are interconnected and form countless synapses.
2. The cardiovascular system – the transport highway of the body
The cardiovascular system supplies the body with oxygen, nutrients and hormones while simultaneously removing waste products.
structure of the cardiovascular system
Heart: Pumps about 7,000 liters of blood through the body every day.
Blood vessels: Arteries, veins and capillaries form an extensive network that transports blood to all cells in the body.
Blood: Consists of red blood cells (transport of oxygen), white blood cells (immune defense), platelets (blood clotting) and plasma.
function of the cardiovascular system
Transport of oxygen and nutrients to the cells.
removal of carbon dioxide and waste products .
Regulation of body temperature and maintenance of homeostasis.
Scientific knowledge
The heart beats an average of 100,000 times a day .
Blood consists of about 55% plasma and 45% blood cells .
3. The respiratory system – the body’s oxygen supplier
The body cannot function without oxygen. The respiratory system ensures that oxygen from the air enters the blood and carbon dioxide is exhaled.
structure of the respiratory system
Lungs: Two spongy organs in which gas exchange takes place.
Respiratory tract: The trachea, bronchi and bronchioles transport air to the alveoli.
function of the respiratory system
Gas exchange: Oxygen from the air enters the blood, while carbon dioxide is exhaled from the blood.
Maintaining pH balance: Breathing influences the body’s acid-base balance.
Scientific knowledge
An adult breathes about 20,000 times a day .
The total surface area of the alveoli is about 70 square meters – the size of a tennis court.
4. The digestive system – the body’s energy source
The digestive system is the "factory" that converts food into energy and nutrients the body needs to maintain homeostasis.
Structure of the digestive system
Mouth: Breaks down food and mixes it with saliva.
Stomach: Releases enzymes and acids to further break down food.
Small intestine: absorption of nutrients.
Large intestine: absorption of water and excretion of waste products.
Function of the digestive system
Nutrient absorption: Breaks down food into glucose, amino acids, vitamins and minerals.
Excretion: Excess or indigestible substances are excreted.
Scientific knowledge
The human intestine has a length of about 9 meters .
There are over 100 trillion bacteria living in the intestines that help with digestion.
5. The muscular system – the engines of the body
Muscles enable movement, posture and stability. They are also involved in temperature regulation.
structure of the muscular system
Skeletal muscles: Voluntary muscles that enable movement.
Smooth muscles: Involuntary muscles are found in the walls of organs (e.g. intestines).
Cardiac muscles: Special type of muscle that makes the heart beat.
function of the muscular system
Movement: All movements of the body require muscle strength.
Heat production: Muscles generate heat and help regulate body temperature.
Scientific knowledge
The human body has about 650 muscles .
The strongest muscle in relation to its size is the tongue .
6. The skeletal system – the supporting structure of the body
The skeleton gives the body stability and protects vital organs.
structure of the skeletal system
Bones: There are 206 bones in the human body.
Cartilage: Soft tissue that acts as cushioning between joints.
Joints: Allow movement and flexibility.
function of the skeletal system
Stability and protection: Protects organs such as the brain, heart and lungs.
Production of blood: Red bone marrow produces blood cells.
Scientific knowledge
The hardest bone in the body is the thigh bone (femur) .
The skeleton renews itself completely every 7-10 years .
Homeostasis – The Balance of the Body
Homeostasis is the body's ability to maintain a stable internal balance, regardless of external changes.
Examples of homeostasis
Body temperature: The body maintains a constant temperature of about 37°C .
Blood sugar level: The hormone insulin regulates blood sugar.
pH: The blood pH remains at around 7.4 , which is crucial for enzyme function.