Systems of the Human Body
• What are the eight life processes?
• What is the difference between a cell, tissue and organ?
• What are the main systems in the human body?
• What roles do these systems perform?
1.1 Life Processes
• All living organisms have certain characteristics that distinguish them from non-living
forms
LIVING THINGS NON- LIVING THINGS
~ Protists ~ Water
~ Plants ~ Soil
~ Animals ~ Air
~ Fungus ~ Minerals
~ Bacteria ~ Light
The basic processes of life include:
1. Responsiveness – is an organism’s ability to detect changes in both their internal and
external environment, react to these changes
2. Movement – refers to all the different types of movement within the body
These may include the movement of molecules from one part of the body to another or the
movement of muscles to allow for locomotion to occur
3. Organisation – refers to the division of labour within an organism
Although different components of the organism may work together, they each have a
specific function to perform
4. Metabolism – includes all chemical reactions that occur within the organism
The break down of food during digestion is an example of this
5. Respiration – the exchange of oxygen and carbon dioxide between the cells and the
external environment
6. Reproduction – the formation of a new organism by its parent(s) organism
This process may occur both sexually or asexually
7. Excretion – the process of removing waste products of digestion and metabolism from
the body
8. Growth – refers to the increase in size of an organism
This process may occur by cells increasing in number or by cells increasing in size
,Cells, Tissues and Organs
• Cells smallest living part of an organism
• Multicellular (more than 1 cell) different cells specialise in order to carry out specific
functions within the organism
• Many cells working together forms a tissue
• Many tissues working together form an organ
*Unicellular – one cell (bacteria: amoeba)
E.g. Many cardiac cells work together to form a cardiac muscle (a tissue)
Cardiac muscle works with the tissue that forms cardiac valves to from the heart which is
an organ
Heart works together with the blood, vessels to form the cardiac system
Systems of the Human Body
• Human body is made of many different systems that all work together in
order for us to perform the necessary life processes
SKELETAL SYSTEM
• Consists of all the bones in our body
• Bones help our bodies to maintain our posture
• Also protect our organs from harm
• Inside our bones is bone marrow
• Bone marrow is important for production of red blood cells
• Cartilage (sits so there is no friction) can be found on the end of the
bones
• Cartilage stops the bones from grinding against each other when we
move
MUSCULAR SYSTEM
• Made of our muscles, tendons and ligaments
• Works together with our skeletal system to allow us to maintain our
posture and move
• Tendons connect the muscles to the bones
• Ligaments join the bones together
RESPIRATORY SYSTEM
• Allows for respiration to take place
• Allows us to inhale and exhale
• Is important because body needs to breathe in oxygen, breathe out carbon dioxide
CIRCULATORY SYSTEM
• Consists of the heart, arteries, capillaries and veins
• Heart pumps blood around the entire body
, • Important as cells in our body need to absorb oxygen, nutrients – excrete carbon
dioxide and waste products
DIGESTIVE SYSTEM
• Allows the body to absorb nutrients (1. Protein, 2. Water, 3. Vitamin, 4. Minerals, 5.
Fat/oil, 6. Carbohydrates, 7. Dairy) from food we eat
• Consists of mouth, oesophagus, stomach, intestines
• Uses enzymes from liver (fat/oil breaks down), pancreas (breaks down carbohydrates-
sugar) to help it with the digestion process
NERVOUS SYTEM
• Consists of the brain and spinal cord
• Nervous system is the control centre for the human body
• It interprets information from our sensory (eyes, noses, ears, skin, tongue) organs,
gives instructions to our muscles, organs
• Nerves are the messengers for nervous system, carry the information to, from the brain
EXCRETORY, ENDOCRINE, REPRODUCTIVE SYSTEMS
• Excretory system is responsible for removing waste from the human body
• Endocrine system is made up of all the glands in our body
• Glands in our body make chemicals called hormones which help our bodies to function
• Hormones help control many parts of our body e.g. appetite and heart rate
• Our reproductive system consists of our sex organs, is responsible for enabling us to
produce young
Digestive System
• Nutrition
- Animals including humans unable to produce their own
food through photosynthesis
- Heterotrophic ~ animals need to eat food in order to gain
nutrients, have to get their own food (Reliant on plants & animals)
- Autotrophic ~ makes it own food, plants break food into soluble nutrients
(this is what our digestive system does)
- Role of digestive system is before animals use this food, first broken down
into simpler, soluble nutrients
Processes in Nutrition
Ingestion – Process of taking in food e.g. eating
Digestion – Process of breaking down (digesting) food
Done in 2 ways: 1. Mechanically *using teeth and tongue (Mastication- chewing)
2. Chemically *Using digestive enzymes etc.
Absorption- Nutrients absorbed into bloodstream (oesophagus), circulated around rest of body
(small intestines) , proving nutrition to all body’s cells (stomach acid- gastric acid)
Egestion: Process where undigested waste is removed from the body in the form of faeces
