Key points
- Specialised animal cells have components that allow them to complete a specific purpose.
- Specialised animal cells include red blood cells, sperm, eggs, nerve cells, muscle cells, ciliated cells, and villi.
Video - What are specialised animal cells?
Can you answer these questions based on the video?
1. What are the three main components of animal cells?
2. How many animal cells could fit across the width of a full stop?
A nucleus, cell membrane and cytoplasm
100
Most cells share features such as having a nucleus, a cell membrane, cytoplasm and mitochondria.
Each type of cell has its own job to do. These cells have special features that allow them to perform their functions effectively.
Red blood cells
Red blood cells carry oxygen around the body, which is needed for respirationA chemical reaction that occurs in the mitochondria of cells in which glucose and oxygen react to produce carbon dioxide and water, releasing energy.They are well suited to this function because:
- They contain haemoglobinThe chemical in red blood cells in which oxygen binds to be carried from the lungs to the rest of the body., which carries oxygen molecules.
- They don't have a nucleus, allowing more space to carry oxygen.
- They are a flat disc shape with dips on both sides (biconcave). This gives them a large surface area, and the best chance of absorbing as much oxygen as they can in the lungs.
Sperm cells
Sperm are the male sex cell. They are made in the testes after pubertyThe time that a teenager becomes sexually mature and physically able to have a baby.. They join with an egg cell during fertilisationThe joining of male and female gametes (sperm and ova or eggs). to form an embryoA bundle of several hundred cells that has developed from a fertilised ovum. which can then develop into a new life. The following features make them well suited to this function:
- A tail moves them towards an egg cell.
- Many mitochondriaTiny parts of cells floating in the cytoplasm where energy is released from glucose. The glucose comes from food. release energy for movement.
- Part of the tip of the head of the sperm, called the acrosome, releases enzymes to digest the egg membrane to allow fertilisation to take place.
- The haploidA cell which contains half the number of chromosomes compared to other cells in the organism. Eg gametes. nucleus contains the genetic material for fertilisation.
- Sperm are produced in large numbers to increase the chance of fertilisation.
Egg cell
Eggs are the female sex cell. They are made in the ovaries before birth. Usually, one egg is released each month during the , but sometimes this number may be higher. They join with a sperm cell during fertilisation to form an embryo which can then develop into a new life. They are well suited to this function because:
- The egg cell鈥檚 cytoplasm contains nutrients for the growth of the early embryo.
- The haploid nucleus contains genetic material for fertilisation.
- The cell membraneThis surrounds the outside of animal cells and controls what can enter and exit it. changes after fertilisation by a single sperm so that no more sperm can enter.
Nerve cells
Nerve cells transmit electrical signals in the nervous systemBody system that includes the brain, spinal cord and nerves.. They are well suited to their function because:
- They are thin, and can be more than one metre long in your spinal cord. This means they can carry messages up and down the body over large distances very quickly.
- Nerve cells have branched connections at each end. These join to other nerve cells, allowing them to pass messages around the body.
- They have a fatty (myelin) sheath that surrounds them. The fatty sheath increases the speed at which the message can travel.
Muscle cells
Muscles cells are found in bundles which make up our muscles. These cells are able to contract (get shorter) and relax (return to original length). There are different types of muscle cell, each perfectly adapted to its function:
- Cardiac (heart) muscle cells contract and relax to pump blood around our bodies for our entire lives. They never get tired.
- Smooth muscle cells make up thin sheets of muscle, such as the stomach lining. They can also be arranged in bundles, or rings, like that in the anus.
- Skeletal muscle is joined to bones. Its cells contract to make bones move and joints bend.
Video - Understanding muscle cells
Ciliated cells
Ciliated cells are found in the airways. They have tiny hairs on their tops called ciliaThe tiny hairs found on the top of ciliated cells which beat. which beat in a rhythm. These hairs move mucus containing dust and other particles upwards and out of the airways. Ciliated cells are also found in the oviductsTubes in the female reproductive system which join the two ovaries to the uterus. Also called fallopian tubes.. Here the tiny hairs beat to move the egg from the ovaries to the uterusThe part of the female reproductive system where a fertilised egg cell develops into an embryo and then a fetus. Also called the womb..
Villi
Villi are structures about one millimetre long in the small intestinesThe part of your digestive system in which digested food is absorbed into the blood. and large intestinesThe part of your digestive system in which water from food and drink is absorbed into the blood.. Millions of them poke out to absorb digested food and water into the blood. They are well suited to this function because:
- They have a large surface area.
- They have thin walls which are only one cell thick.
- The cells of the lining have tiny hairs to absorb more food and water.
Test your knowledge
Quiz
Test questions
What are the adaptations of red blood cells?
- Red blood cells contain haemoglobin, which carries oxygen molecules.
- They don't have a nucleus, allowing more space to carry oxygen.
- They are a flat disc shape with dips on both sides (biconcave) which gives them a large surface area.
What are the adaptations of nerve cells?
- Nerve cells are thin and long so they can carry messages all over the body very quickly.
- They have branched connections at each end to allow electrical signals to pass to other cells.
- They have a fatty (myelin) sheath that surrounds them and increases the speed at which the electrical signal can travel.
Teaching resources
Looking for even more teaching resources to engage your students? This series of short films introduces the key concepts in Biology, exploring wildlife and the natural world.
大象传媒 Teach has thousands of free, curriculum-linked resources to help deliver lessons - all arranged by subject and age group.
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