The Integumentary System More Than Skin Deep Mitosis

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

TEKS The student knows the structures and functions of nucleic acids in the mechanisms of genetics. The student is expected to (C) compare the processes of mitosis and meiosis and their significance to sexual 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

Questions What is all body tissue composed of? What is mitosis?

Elaborate Most common and preventable disease of the integument is skin cancer Skin cancer - most common form of cancer in the US Cancer - general term for over 100 diseases our body, including the skin Cancer - uncontrolled growth of abnormal and damaged cells. What is skin cancer?

Skin Cancer

Skin Cancer One cell is damaged by the sun and is no longer a normal skin cell. This cell continues to grow uncontrolled and builds up in a location of the body making a tumor. Malignant tumors can invade and destroy other tissues and spread to other parts of the body through the blood stream and lymphatic system.

Lymphatic System Network of Vessels Carries Lymph- Colorless Fluid Lymph is carried to organs including the lymph nodes, spleen, thymus, and to cells throughout the body.

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

Types of Skin Cancer Basal cell carcinoma Squamous cell carcinoma Melanoma

Basal Cell and Squamous Cell These are the most common forms of skin cancers Basal Cell – Most common type Starts in the basal cells Slow Growing If left untreated, invades cartilage and bone causing disfigurement Squamous cell – Second most common Starts in the squamous cells Most common form of skin cancer in those with darker skin Starts as a nodule or red patch with well-defined outline May metastasize if left untreated

Melanoma Less common than Basal and Squamous cell cancers MOST DEADLY Starts in melanocytes Linked to severe sunburns in childhood and adolescence Caused by short, intense, excessive, exposure to ultraviolet light Every blistering sunburn you get before you turn 18 increases your chances of developing melanoma

Questions What are the three types of skin cancer? Which types are the most common? Which skin cancer is most serious? Why Which cancer is caused by “short, intense, excessive, exposure” to ultraviolet light? Which is the most common skin cancer in people with darker skin?

Treatments Melanoma Basal and Squamous Surgery is most common, and the only certain cure Basal and Squamous Surgery Freezing Burning Scraping Creams and lotion-based chemotherapy Radiation