The Integumentary The Integumentary SystemSystem

More Than Skin DeepMore Than Skin Deep

MitosisMitosis

TAKSTAKS

• Objective 2Objective 2 – The student will – The student will demonstrate an understanding demonstrate an understanding of living systems and the of living systems and the environment.environment.

TEKSTEKS

• The student knows the structures The student knows the structures and functions of nucleic acids in the and functions of nucleic acids in the mechanisms of genetics. The mechanisms of genetics. The student is expected tostudent is expected to

(C) compare the processes of (C) compare the processes of mitosismitosis and meiosis and their significance to and meiosis and their significance to sexual and asexual reproductionsexual and asexual reproduction

Engage Grace’s Story

Explore 1: Onion Root Tip

How many anaphases can you spot?

What phase is represented by the cells with the dark circles?

Exploration 2: Onion/Whitefish Lab

Cells in Action Mitosis Mitosis Animation

Explain:Mitosis (Nuclear Division)

Mitosis is considered nuclear division since the steps only refer to the contents of the nucleus.

There are 4 steps. Prophase P Metaphase M Anaphase A Telophase T

Prophase

Early Metaphase

Late Metaphase

Anaphase

Telophase

Interphase Review (G1, S, G2)

Chromosomes are replicated Chromsomes appear as threadlike coils

(chromatin) at the start, but each chromosome and its copy (homologous chromosome) change to sister chromatids at the end of this phase

Prophase The nucleus disappears DNA Condenses The chromatid pairs

(sister chromatids) are joined by a centromere.

The thread-like spindle fibers appear.

The centrioles move toward the poles.

Metaphase The shortest stage of

mitosis. Sister Chromatids

attach to spindle fibers Chromatid pairs line up

along the equator (middle) of the cell.

Why does this occur? So that each new cell

will receive one chromatid from the pair.

Anaphase The chromatid pairs

separate and the separated chromosomes move in opposite directions.

The spindle fibers contract and somehow pull them toward the poles.

Telophase

The cell begins to separate.

Two new nuclei begin to reappear.

Chromosomes decondense to form chromatin

The spindle fibers disappear.

Cytokinesis Final separation into 2 new daughter cells. Cells are identical in the type and number of

chromosomes it contains. Each cell has its own nucleus with identical

DNA If a cell containing 46 chromosomes undergoes mitosis,

how many chromosomes does each of its daughter cells contain?

46 Where did the extra 46 chromosomes come from? The S phase of the cell cycle.

Stages of Mitosis

Name Each

Anaphase

Early Metaphase

Prophase

Telophase

Late Metaphase

QuestionsQuestions

• What is all body tissue composed of?What is all body tissue composed of?

• What is mitosis?What is mitosis?

ElaborateElaborate

• Most common and preventable disease of Most common and preventable disease of the integument is skin cancerthe integument is skin cancer

• Skin cancer - most common form of cancer Skin cancer - most common form of cancer in the USin the US

• Cancer - general term for over 100 Cancer - general term for over 100 diseases our body, including the skindiseases our body, including the skin

• Cancer - uncontrolled growth of abnormal Cancer - uncontrolled growth of abnormal and damaged cells.and damaged cells.

• What is skin cancer?What is skin cancer?

Skin CancerSkin Cancer

Skin CancerSkin Cancer

• One cell is damaged by the sun and One cell is damaged by the sun and is no longer a normal skin cell.is no longer a normal skin cell.

• This cell continues to grow This cell continues to grow uncontrolled and builds up in a uncontrolled and builds up in a location of the body making a tumor.location of the body making a tumor.

• Malignant tumors can invade and Malignant tumors can invade and destroy other tissues and spread to destroy other tissues and spread to other parts of the body through the other parts of the body through the blood stream and lymphatic system.blood stream and lymphatic system.

Lymphatic SystemLymphatic System

• Network of VesselsNetwork of Vessels

• Carries Lymph- Carries Lymph- Colorless FluidColorless Fluid

• Lymph is carried to Lymph is carried to organs including the organs including the lymph nodes, lymph nodes, spleen, thymus, and spleen, thymus, and to cells throughout to cells throughout the body.the body.

MetastasisMetastasis

• When cancer spreads to other parts When cancer spreads to other parts of the body this is called metastasisof the body this is called metastasis

Types of Skin CancerTypes of Skin Cancer

• Basal cell carcinomaBasal cell carcinoma

• Squamous cell carcinomaSquamous cell carcinoma

• MelanomaMelanoma

Basal Cell and Squamous Basal Cell and Squamous CellCell• These are the most common forms of These are the most common forms of

skin cancersskin cancers• Basal Cell – Most common typeBasal Cell – Most common type

– Starts in the basal cellsStarts in the basal cells– Slow GrowingSlow Growing– If left untreated, invades cartilage and If left untreated, invades cartilage and

bone causing disfigurementbone causing disfigurement• Squamous cell – Second most Squamous cell – Second most

commoncommon– Starts in the squamous cellsStarts in the squamous cells– Most common form of skin cancer in Most common form of skin cancer in

those with darker skinthose with darker skin– Starts as a nodule or red patch with well-Starts as a nodule or red patch with well-

defined outlinedefined outline– May metastasize if left untreatedMay metastasize if left untreated

MelanomaMelanoma• Less common than Basal and Less common than Basal and

Squamous cell cancersSquamous cell cancers• MOST DEADLYMOST DEADLY• Starts in melanocytesStarts in melanocytes• Linked to severe sunburns in Linked to severe sunburns in

childhood and adolescencechildhood and adolescence• Caused by short, intense, excessive, Caused by short, intense, excessive,

exposure to ultraviolet lightexposure to ultraviolet light• Every blistering sunburn you get Every blistering sunburn you get

before you turn 18 increases your before you turn 18 increases your chances of developing melanomachances of developing melanoma

QuestionsQuestions

• What are the three types of skin cancer?What are the three types of skin cancer?

• Which types are the most common?Which types are the most common?

• Which skin cancer is most serious? WhyWhich skin cancer is most serious? Why

• Which cancer is caused by “short, Which cancer is caused by “short, intense, excessive, exposure” to intense, excessive, exposure” to ultraviolet light?ultraviolet light?

• Which is the most common skin cancer Which is the most common skin cancer in people with darker skin?in people with darker skin?

TreatmentsTreatments

• MelanomaMelanoma– Surgery is most common, and the only certain Surgery is most common, and the only certain

curecure

• Basal and SquamousBasal and Squamous– SurgerySurgery– FreezingFreezing– BurningBurning– ScrapingScraping– Creams and lotion-based chemotherapyCreams and lotion-based chemotherapy– RadiationRadiation