BIOLOGY · Stage 7 · Chapter 2: Cells and Organisation
Biology 2.8 Tissues and organs in animals
5 min read 7 parts Lesson 8 of 10
Lesson summary
2.8 Tissues and organs in animals — Alhussan International Academy — Biology (Stages 7–9) notes: Describe the main animal tissues, give examples of organs and organ systems, and explain how they work together.Cells — the building blocks of all living organisms.Tissues = many spec…
- Whole organism
- Order of size
- Glandular tissue
- Cardiac muscle
- Smooth muscle
- Skeletal muscle
Section 1 of 7Levels of organisation
- Cells
- the building blocks of all living organisms.
- Tissues = many specialised cells of the same type working together to carry out a particular function.
- Organs = several different tissues working together to carry out a particular function.
- Organ systems = several different organs working together to carry out a particular function.
- Whole organism
- many different organs and organ systems all working together.
- Order of size
- cell, tissue, organ, organ system, organism, increasing in complexity.
- Example: muscle cell, muscle tissue, stomach, digestive system, human.
Section 2 of 7Animal tissues
| Tissue | Function | Where found |
|---|---|---|
| Muscle | Contracts to produce movement | Heart, limbs, stomach wall |
| Nervous | Carries electrical impulses and coordinates responses | Brain, spinal cord, nerves |
| Epithelial | Covers and lines surfaces, protects and absorbs | Skin, lining of gut and airways |
| Connective | Supports and joins other tissues | Bone, cartilage, blood, tendons |
- Glandular tissue
- it makes secretions such as enzymes or hormones and is found in many organs.
Section 3 of 7Types of muscle tissue
- Cardiac muscle
- heart muscle.
- Smooth muscle
- found in the gut and blood vessels.
- Skeletal muscle
- attached to bones.
- Contraction
- all the cells in a muscle tissue contract together to move parts of the body.
Section 4 of 7Animal organs
| Organ | Function |
|---|---|
| Brain | Controls the body |
| Lungs | Take in oxygen and remove carbon dioxide |
| Heart | Pumps blood |
| Stomach | Digests food |
| Liver | Removes toxins from the blood and produces bile to help digestion |
| Kidney | Filters the blood and produces urine |
| Intestine | Absorbs nutrients from food |
| Bladder | Stores urine |
- Skin
- it is the biggest organ, about 16% of body mass and about 2 m2 in area when spread flat.
- It is made of several tissues including fat, nervous, connective and elastic tissue.
- Brain
- an organ made of many tissues including nervous tissue, connective tissue and fat tissue.
Section 5 of 7The stomach as an organ
- Muscle tissue
- it contracts in the wall to churn and mix the food.
- Glandular tissue
- it produces digestive juices containing enzymes and hydrochloric acid, which kills bacteria.
- Epithelial tissue
- it lines the inside and protects it with a layer of mucus.
- Nervous tissue and blood vessels
- they control the activity and supply oxygen.
- System
- the stomach is part of the digestive system with the mouth, gullet, small and large intestines, liver and pancreas.
Section 6 of 7Human organ systems
| System | Main organs | Function |
|---|---|---|
| Digestive | Gullet, stomach, intestines, liver | Breaks down food, absorbs nutrients into the blood and removes undigested waste |
| Circulatory | Heart, blood vessels, blood | Transports materials around the body |
| Respiratory | Lungs, airways | Gas exchange |
| Nervous | Brain, spinal cord | Detects stimuli and coordinates responses |
| Skeletal and muscular | Bones, muscles | Support and movement |
| Excretory | Kidneys, bladder | Removes waste from the blood |
| Reproductive | Testes, ovaries, uterus | Produces new human beings |
Section 7 of 7Organ systems work together
- Dependence
- the digestive system supplies glucose, the respiratory system supplies oxygen, and the circulatory system delivers both to every cell for respiration.
- During exercise
- the nervous system detects the need to move and the muscular system contracts muscles that pull on the skeleton.
- The respiratory and circulatory systems work faster to deliver oxygen and glucose.
- The blood removes heat and carbon dioxide, and the skin sweats to cool the body.
- Fault in one system
- it reduces what the whole body can do, as with a damaged heart valve.
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