Cell Differentiation AS Biology Note a major source of ideas and images is from: http://asweknowit.net/MIDDLE_SCH/DWA%205%20marshall.htm

In the centre of the diagram are three of the early steps in the development of a mammal. ZYGOTE  BLASTOCYST  GASTRULA On the top and bottom are some of the fully-differentiated cell types that will eventually form in the adult.

Animal embryos go from a single zygote cell through a series of many divisions to a hollow ball of cells called a blastula. A dent on the surface becomes deeper in a process called gastrulation, until the ball is a two-layered bowl. The opening of the bowl will be an opening into the animal - in protostomes, the mouth, and in deuterostomes, the anus. Each layer of the gastrula , called germ layers, will go one to be different parts of the animal. The outer layer will be the ectoderm, which gives rise to the surface features (skin and related structures, including shells and external skeletons) and the nervous system, which develops from a thickened surface plate and which extends nerves into the other tissues during later development. The inner layer, the endoderm, goes on to be digestive system and related structures (including our lungs). Between the layers a mesoderm appears (as a mass in protostomes and an outgrowth of endoderm in deuterostomes) and will eventually contribute to the rest of the internal organs and structures, including muscles and internal skeletons.

Animal embryos go from a single zygote cell through a series of many divisions to a hollow ball of cells called a blastula.

A dent on the surface becomes deeper in a process called gastrulation, until the ball is a two-layered bowl.

The opening of the bowl will be an opening into the animal - in protostomes, the mouth, and in deuterostomes, the anus.

Each layer of the gastrula , called germ layers, will go one to be different parts of the animal.

The outer layer will be the ectoderm, which gives rise to the surface features (skin and related structures, including shells and external skeletons) and the nervous system, which develops from a thickened surface plate and which extends nerves into the other tissues during later development.

The inner layer, the endoderm, goes on to be digestive system and related structures (including our lungs).

Between the layers a mesoderm appears (as a mass in protostomes and an outgrowth of endoderm in deuterostomes) and will eventually contribute to the rest of the internal organs and structures, including muscles and internal skeletons.

1. Germ Cells - progenitors of the gametes. move through the gut to the developing gonads (ovaries, testes) multiply by mitosis, followed by meiosis and differentiation into either eggs or sperm (mature gametes).

- progenitors of the gametes.

move through the gut to the developing gonads (ovaries, testes)

multiply by mitosis, followed by meiosis and differentiation into either eggs or sperm (mature gametes).

2. Somatic cells are any cells forming the body of an organism internal organs, skin, bones, blood, and connective tissue

are any cells forming the body of an organism

internal organs, skin, bones, blood, and connective tissue

3. Stem cells found in most multi-cellular organisms ability to renew themselves through mitosis, while maintaining undifferentiated state differentiate into a diverse range of specialized cell types

found in most multi-cellular organisms

ability to renew themselves through mitosis, while maintaining undifferentiated state

differentiate into a diverse range of specialized cell types

Totipotent (or omnipotent ) stem cells can differentiate into embryonic and extraembryonic cell types. Such cells can construct a complete, viable, organism. Pluripotent stem cells can differentiate into nearly all cells, i.e. cells derived from any of the three germ layers. Unipotent cells can produce only one cell type, their own, but have the property of self-renewal which distinguishes them from non-stem cells (e.g. muscle stem cells).

Embryonic Stem Cells Embryonic stem cells (ES cells) are derived from the inner cell mass of an early stage embryo known as a blastocyst. Human embryos reach the blastocyst stage 4–5 days post fertilization, at which time they consist of 50–150 cells. Pluripotent - able to differentiate into all derivatives (more than 220 cell types) of the three primary germ layers: ectoderm, endoderm, and mesoderm.

Embryonic stem cells (ES cells) are derived from the inner cell mass of an early stage embryo known as a blastocyst.

Human embryos reach the blastocyst stage 4–5 days post fertilization, at which time they consist of 50–150 cells.

Pluripotent - able to differentiate into all derivatives (more than 220 cell types) of the three primary germ layers: ectoderm, endoderm, and mesoderm.

Adult stem cells undifferentiated cells, found throughout the body after embryonic development multiply by cell division to replenish dying cells and regenerate damaged tissues. also known as somatic stem cells scientific interest - their ability to divide or self-renew indefinitely, and generate all the cell types of the organ from which they originate, potentially regenerating the entire organ from a few cells. use in research and therapy is not controversial as they are derived from adult tissue samples rather than human embryos. mainly been studied in humans, mice and rats.

undifferentiated cells, found throughout the body after embryonic development

multiply by cell division to replenish dying cells and regenerate damaged tissues.

also known as somatic stem cells

scientific interest - their ability to divide or self-renew indefinitely, and generate all the cell types of the organ from which they originate, potentially regenerating the entire organ from a few cells.

use in research and therapy is not controversial as they are derived from adult tissue samples rather than human embryos.

mainly been studied in humans, mice and rats.

Tissue - a bunch of cells working together on one job Organ - lots of tissues working together Organ system - a group of organs working together for a particular function Organism - many organ systems working together

Tissue - a bunch of cells working together on one job

Organ - lots of tissues working together

Organ system - a group of organs working together for a particular function

Organism - many organ systems working together

1. Epithelial tissue lines most body surfaces and protects other tissues from damage and dehydration. You don't have to know these types, but here is where they are...JUST think "Linings" or "Covers"

1. Epithelial tissue lines most body surfaces

and protects other tissues from damage and dehydration.

You don't have to know these types,

but here is where they are...JUST think "Linings" or "Covers"

Epithelial tissue

Nervous Tissue Consists of nerve cells, which carry information throughout the body

Consists of nerve cells, which carry information throughout the body

Central Nervous System Central Nervous System (CNS) = The Spinal Cord + Brain Spinal cord = the main super highway of nerve TISSUE transmitting or sending signals to the brain The Brain = the master computer of TISSUE receiving and sending messages INPUT: receiving messages from stimulus = signals or information we detect with our senses (connected to nerves in the PNS) OUTPUT: sending out messages signals or information (a response)

Central Nervous System (CNS)

= The Spinal Cord + Brain

Spinal cord = the main super highway of nerve TISSUE transmitting or sending signals to the brain

The Brain = the master computer of TISSUE receiving and sending messages

INPUT: receiving messages from stimulus = signals or information we detect with our senses (connected to nerves in the PNS)

OUTPUT: sending out messages signals or information (a response)

Peripheral Nervous System Peripheral (outside, or away from the centre) Nervous System (PNS)  nerves leading to and away from the CNS THE CNS = highway; or big bundle of many wires THE PNS = roads to the highway; or single wires leading to the big bundle

Peripheral (outside, or away from the centre) Nervous System (PNS)

 nerves leading to and away from the CNS

THE CNS = highway; or big bundle of many wires

THE PNS = roads to the highway; or single wires leading to the big bundle

Nerves are basically an extension of your brain...they are connected, and communicate messages with each other within fractions of a second

"...each of the 10 billion neurons in the human brain has the possibility of connections to 1 with 28 zeros after it!!! That's 10,000,000,000,000,000,000,000,000,000 connections! It means that the total combinations in the brain, if written out, would be 1 followed by 10.5 kilometres of zeros!!!"

"...each of the 10 billion neurons in the human brain

has the possibility of connections to 1 with 28 zeros after it!!!

That's 10,000,000,000,000,000,000,000,000,000 connections!

It means that the total combinations in the brain, if written out, would be 1 followed by 10.5 kilometres of zeros!!!"

Muscle Tissue - Smooth - Skeletal - Cardiac

Connective Tissue

Connective Tissue maintains the form of the body and its organs provides cohesion and internal support includes bone, ligaments, tendons, cartilage, and adipose tissue (fat). Its major components are different kinds of cells and extracellular fibres and ground substance, which varies in consistency from thin gel to rigid structure.

maintains the form of the body and its organs

provides cohesion and internal support

includes bone, ligaments, tendons, cartilage, and adipose tissue (fat).

Its major components are different kinds of cells and extracellular fibres and ground substance, which varies in consistency from thin gel to rigid structure.

Connective Tissue 1. Blood 2. Fat 3. Collagen - the main protein of connective tissue - about 25% of the total protein content - a protein found in bone , cartilage, teeth, ligaments, tendons, skin, blood vessels, eyes (in the cornea and lens) - strong Ligaments = bone to bone connections Tendons = muscle to muscle, or muscle to bone connections

1. Blood

2. Fat

3. Collagen

- the main protein of connective tissue - about 25% of the total protein content

- a protein found in bone , cartilage, teeth, ligaments, tendons, skin, blood vessels, eyes (in the cornea and lens) - strong

Ligaments = bone to bone connections

Tendons = muscle to muscle, or muscle to bone connections

Look at these pictures and think of the relationships and how they work together for the benefit of ALL...you. What if one fails? Look at each picture and imagine one failing, which one will be affected next?