Cells,Tissues,Organs,System Gab
Content
SCIENCE : HOW DO WE DEFINE SCIENCE?
1. (from Latin: scientia, meaning "knowledge") is a systematic enterprise of gathering knowledge about the world and organizing and condensing that knowledge into testable laws and theories 2. According to Webster's New Collegiate Dictionary, the definition of science is "knowledge attained through study or practice," or "knowledge covering general truths of the operation of general laws, esp. as obtained and tested through scientific method [and] concerned with the physical world." 3. Science refers to a system of acquiring knowledge. This system uses observation and experimentation to describe and explain natural phenomena. The term science also refers to the organized body of knowledge people have gained using that system. Less formally, the word science often describes any systematic field of study or the knowledge gained from it.
What is the purpose of science? Perhaps the most general description is that the purpose of science is to produce useful models of reality.
PROCESS SKILLS FOR LIFE SCIENCE (05)
Training Guide prepared by Karen L. Lancour, National Supervisor
This event is a lab-oriented competition involving the fundamental science processes of a middle school life-science program. The event is not meant to be a comprehensive biology course. If specific content is needed when students are being tested on certain process skills, the supervisor will provide that content. SCIENCE PROCESS SKILLS The event consists of a series of biological questions or tasks that involve the use of one or more process skills. Science process skills are classified as basic skills and integrated skills. These skills can be accessed by applying them to a series of lab station activities which are included in the Guide for Supervisors, Coaches and Students. Tips to assist students in their preparations are also included in this guide.
Basic Science Process Skills:
• Observing - using your senses to gather information about an object or event. It is a description of what was actually perceived. This information is considered qualitative data. • Measuring - using standard measures or estimations to describe specific dimensions of an object or event. This information is considered quantitative data. • Inferring - formulating assumptions or possible explanations based upon observations. • Classifying - grouping or ordering objects or events into categories based upon characteristics or defined criteria. • Predicting - guessing the most likely outcome of a future event based upon a pattern of evidence. • Communicating - using words, symbols, or graphics to describe an object, action or event.
Integrated Science Process Skills:
• Formulating Hypotheses - stating the proposed solutions or expected outcomes for experiments. These proposed solutions to a problem must be testable. • Identifying of Variables - stating the changeable factors that can affect an experiment. It is important to change only the variable being tested and keep the rest constant. The one being manipulated is the independent variable; the one being measured to determine its response is
the dependent variable; and all variables that do not change and may be potential independent variables are constants. • Defining Variables Operationally - explaining how to measure a variable in an experiment. • Describing Relationships Between Variables - explain relationships between variables in an experiment such as between the independent and dependant variables plus the standard of comparison. • Designing Investigations - designing an experiment by identifying materials and describing appropriate steps in a procedure to test a hypothesis. • Experimenting - carrying out an experiment by carefully following directions of the procedure so the results can be verified by repeating the procedure several times. • Acquiring Data - collecting qualitative and quantitative data as observations and measurements. • Organizing Data in Tables and Graphs - making data tables and graphs for data collected. • Analyzing Investigations and Their Data - interpreting data statistically, identifying human mistakes and experimental errors, evaluating the hypothesis, formulating conclusions, and recommending further testing where necessary. • Understanding Cause and Effect Relationships - what caused what to happen and why. • Formulating Models - recognizing patterns in data and making comparisons to familiar objects or ideas.
CELLS
The cell is the functional basic unit of life. It was discovered by Robert Hooke and is the functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. Some organisms, such as most bacteria, are unicellular (consist of a single cell). Other organisms, such as humans, are multicellular. (Humans have about 100 trillion or 1014 cells; a typical cell size is 10 µm; a typical cell mass is 1 nanogram. The largest cells are about 135 µm in the anterior horn in the spinal cord while granule cells in the cerebellum, the smallest, can be some 4 µm and the
longest cell can reach from the toe to the lower brain stem (Pseudounipolar cells).[2]) The largest known cells are unfertilised ostrich egg cells which weigh 3.3 pounds In 1835, before the final cell theory was developed, Jan Evangelista Purkyně observed small "granules" while looking at the plant tissue through a microscope. The cell theory, first developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann, states that all organisms are composed of one or more cells, that all cells come from preexisting cells, that vital functions of an organism occur within cells, and that all cells contain the hereditary information necessary for regulating cell functions and for transmitting information to the next generation of cells. The word cell comes from the Latin cellula, meaning, a small room. The descriptive term for the smallest living biological structure was coined by Robert Hooke in a book he published in 1665 when he compared the cork cells he saw through his microscope to the small rooms monks lived in. The cell is one of the most basic units of life. There are millions of different types of cells. There are cells that are organisms onto themselves, such as microscopic amoeba and bacteria cells. And there are cells that only function when part of a larger organism, such as the cells that make up your body. The cell is the smallest unit of life in our bodies. In the body, there are brain cells, skin cells, liver cells, stomach cells, and the list goes on. All of these cells have unique functions and features. And all have some recognizable similarities. All cells have a 'skin', called the plasma membrane, protecting it from the outside environment. The cell membrane regulates the movement of water, nutrients and wastes into and out of the cell. Inside of the cell membrane are the working parts of the cell. At the center of the cell is the cell nucleus. The cell nucleus contains the cell's DNA, the genetic code that coordinates protein synthesis. In addition to the nucleus, there are many organelles inside of the cell - small structures that help carry out the day-to-day operations of the cell. One important cellular organelle is the ribosome. Ribosomes participate in protein synthesis. The transcription phase of protein synthesis takes places in the cell nucleus. After this step is complete, the mRNA leaves the nucleus and travels to the cell's ribosomes, where translation occurs. Another important cellular organelle is the mitochondrion. Mitochondria (many mitochondrion) are often referred to as the power plants of the cell because many of the reactions that produce energy take place in mitochondria. Also important in the life of a cell are the lysosomes. Lysosomes are organelles that contain enzymes that aid in the digestion of nutrient molecules and other materials. Below is a labelled diagram of a cell to help you identify some of these structures.
There are many different types of cells. One major difference in cells occurs between plant cells and animal cells. While both plant and animal cells contain the structures discussed above, plant cells have some additional specialized structures. Many animals have skeletons to give their body structure and support. Plants do not have a skeleton for support and yet plants don't just flop over in a big spongy mess. This is because of a unique cellular structure called the cell wall. The cell wall is a rigid structure outside of the cell membrane composed mainly of the polysaccharide cellulose. As pictured at left, the cell wall gives the plant cell a defined shape which helps support individual parts of plants. In addition to the cell wall, plant cells contain an organelle called the chloroplast. The chloroplast allow plants to harvest energy from sunlight. Specialized pigments in the chloroplast (including the common green pigment chlorophyll) absorb sunlight and use this energy to complete the chemical reaction: 6 CO2 + 6 H2O + energy (from sunlight) later use. Organisms contain many different types of cells that perform many different functions. In the next lesson, we will examine how individual cells come together to form larger structures in the human body. C6H12O6 + 6 O2 In this way, plant cells manufacture glucose and other carbohydrates that they can store for
TISSUES
Tissue is a cellular organizational level intermediate between cells and a complete organism. Hence, a tissue is an ensemble of cells, not necessarily identical, but from the same origin, that together carry out a specific function. Organs are then formed by the functional grouping together of multiple tissues.
A layer or group of cells that collectively perform a specific function forms tissues. These are the main types of tissues found body functions.
Tissues are composed of groups or layers of cells, which perform a collectively specific
in
the and
human their
function. Different types of tissues have different structures that are specific to their function. Tissues can be held together by a sticky coating called an „extracellular matrix‟ or the matrix may weave the cells of tissues together. The Latin word for tissue is derived from the verb
texere, “to weave”.
These are the major tissue types in the human body: Connective Epithelial Muscular Nervous system Lymphatic
Connective Tissue Connective tissue is made up of cells and protein fibers and provides support for other body tissues. The main proteins in connective tissue are collagen and elastin. There are five types of connective tissue. They are: Loose connective tissue: including adipose tissue (fat storage) Dense connective tissue Bone Blood Cartilage
Epithelial Tissue Epithelial tissue, often called epithelium, is comprised of tightly packed cells, arranged to form layers. Epithelium provides many functions, including absorption, excretion, protection, reproduction, secretion and sensory reception. Epithelial cells are constantly renewing and replacing the dead or inactive cells. The two main epithelial tissue types are called a carcinoma. The study of or, tissue in is known as histology tools for connection tissues which and last in are tissue with the is lining and glandular. You can develop colorectal cancer in both of them. Cancer of epithelial tissue is
disease, histopathology. The classical studying block in paraffin
embedded and then sectioned, the histological microscope. decades, stain, In the optical of electron the couple
developments
microscopy, immunofluorescence, and the use of frozen tissue sections have enhanced the detail that can be observed in tissues. With these tools, the classical appearances of tissues can be examined in health and disease, enabling considerable refinement of clinical diagnosis and prognosis.
ORGANS
In biology and (Latin: anatomy, an
organ ὄργανον
organum,
"organ,
"instrument, tool", from Greek organon, instrument, tool" is a collection of tissues joined in structural unit to serve a common function. Usually there is a main tissue and
sporadic tissues. The main tissue
is the one that is unique for the specific organ. For example, main tissue in the heart is the myocardium, while sporadic are the nerves, blood, connective.
ORGAN SYSTEMS
List of major mammalian organ systems There are eleven major organ systems found in mammals. Mammals such as humans have a variety of organ systems. These specific systems are also widely studied in human anatomy. Circulatory system: pumping and channeling blood to and from the body and lungs with heart, blood and blood vessels. Digestive system: digestion and processing food with salivary glands, esophagus, stomach, liver, gallbladder, pancreas, intestines, rectum and anus. Endocrine system: communication within the body using hormones made by endocrine glands such as the hypothalamus, pituitary or pituitary gland, pineal body or pineal gland, thyroid, parathyroids and adrenals, i.e., adrenal glands. Excretory system: kidneys, ureters, bladder and urethra involved in fluid balance, electrolyte balance and excretion of urine. Integumentary system: skin, hair and nails. Lymphatic system: structures involved in the transfer of lymph between tissues and the blood stream, the lymph and the nodes and vessels that transport it including the Immune system: defending against disease-causing agents with leukocytes, tonsils, adenoids, thymus and spleen. Muscular system: movement with muscles. Nervous system: collecting, transferring and processing information with brain, spinal
cord, peripheral nerves and nerves. Reproductive system: the sex organs, such as ovaries, fallopian tubes, uterus, vagina, mammary glands, testes, vas deferens, seminal vesicles, prostate and penis. Respiratory system: the organs used for breathing, the pharynx, larynx, trachea, bronchi, lungs and diaphragm. Skeletal system: structural support and protection with bones, cartilage, ligaments and tendons External features Common names of well known parts of the human body, from top to bottom: Skin
Head – Forehead – Eye – Ear – Nose – Mouth – Tongue – Teeth – Jaw – Face – Cheek – Chin Neck – Throat – Adam's apple – Shoulders Arm – Elbow – Wrist – Hand – Fingers – Thumb Spine – Chest – Breast – Ribcage Abdomen – Belly button – Sex organs (Penis/Scrotum or Clitoris/Vagina) – Rectum – Anus Hip – Buttocks – Leg – Thigh – Knee – Calf – Heel – Ankle – Foot – Toes
Internal organs Common names of internal organs (in alphabetical order):
Adrenal glands – Appendix – Bladder – Brain – Duodenum – Gall bladder – Heart – Intestines – Kidney –Liver– Lungs – Ovaries – Pancreas – Parathyroid gland – Pituitary gland – Prostate gland – Spleen – Stomach – Thymus gland – Thyroid gland – Testicles – Womb.
Top 10 Useless Organs
10 - Plica Semilunaris (3rd eyelid) - You may not know it, but you have a third eyelid. Pull open the two more noticeable eyelids and take a look - it's located right in the corner by the tear duct. The third eyelid is left over from what's known as a "nictitating membrane," which is still present in animals like chickens, lizards and sharks 9 - Body Hair - No doubt we were once hairier. Up until about 3 million years ago, we were covered with it. But by the time Homo erectus arrived, the ability to sweat meant we could shed our wooly ways. 8 – Sinuses - Doctors don't really know much about sinuses, only that we have a lot of them. Possibilities for their function range from insulating our eyes to changing the pitch and tone of our voice. 7 – Adenoids - Adenoids trap bacteria, but they're also prone to swelling and infection. Just ask any 7-year-old. Luckily, our adenoids shrink with age and are often removed, along with... 6 – Tonsils - Also prone to swelling and infection. If you have them by your 30s, it's almost an accomplishment 5 – Coccyx - More useful as a game-winning Scrabble word than part of the anatomy, the coccyx, or tailbone, is several fused vertebrae left over from the olden days when we had tails. 4- Erector Pili - When were hairier the erector pili made the hairs stand on end when we needed to appear bigger and scarier. Now, it just gives us goose bumps. 3 - Wisdom Teeth - Back in the day, when we ate mammoth meat off the bone and didn't floss afterward, our teeth tended to fall out. Therefore, when those reserve molars, aka "wisdom teeth," came in they were welcomed. Nowadays, fluoride and dental plans have just made them a huge pain 2 – Appendix - Darwin claimed the appendix was useful for digestion during our early plant-eating years; it's dwindled down to little since we started eating more digestible foods. 1- Male Nipples - Because, they don't secrete milk at all, just all for show and nothing more.
1. (from Latin: scientia, meaning "knowledge") is a systematic enterprise of gathering knowledge about the world and organizing and condensing that knowledge into testable laws and theories 2. According to Webster's New Collegiate Dictionary, the definition of science is "knowledge attained through study or practice," or "knowledge covering general truths of the operation of general laws, esp. as obtained and tested through scientific method [and] concerned with the physical world." 3. Science refers to a system of acquiring knowledge. This system uses observation and experimentation to describe and explain natural phenomena. The term science also refers to the organized body of knowledge people have gained using that system. Less formally, the word science often describes any systematic field of study or the knowledge gained from it.
What is the purpose of science? Perhaps the most general description is that the purpose of science is to produce useful models of reality.
PROCESS SKILLS FOR LIFE SCIENCE (05)
Training Guide prepared by Karen L. Lancour, National Supervisor
This event is a lab-oriented competition involving the fundamental science processes of a middle school life-science program. The event is not meant to be a comprehensive biology course. If specific content is needed when students are being tested on certain process skills, the supervisor will provide that content. SCIENCE PROCESS SKILLS The event consists of a series of biological questions or tasks that involve the use of one or more process skills. Science process skills are classified as basic skills and integrated skills. These skills can be accessed by applying them to a series of lab station activities which are included in the Guide for Supervisors, Coaches and Students. Tips to assist students in their preparations are also included in this guide.
Basic Science Process Skills:
• Observing - using your senses to gather information about an object or event. It is a description of what was actually perceived. This information is considered qualitative data. • Measuring - using standard measures or estimations to describe specific dimensions of an object or event. This information is considered quantitative data. • Inferring - formulating assumptions or possible explanations based upon observations. • Classifying - grouping or ordering objects or events into categories based upon characteristics or defined criteria. • Predicting - guessing the most likely outcome of a future event based upon a pattern of evidence. • Communicating - using words, symbols, or graphics to describe an object, action or event.
Integrated Science Process Skills:
• Formulating Hypotheses - stating the proposed solutions or expected outcomes for experiments. These proposed solutions to a problem must be testable. • Identifying of Variables - stating the changeable factors that can affect an experiment. It is important to change only the variable being tested and keep the rest constant. The one being manipulated is the independent variable; the one being measured to determine its response is
the dependent variable; and all variables that do not change and may be potential independent variables are constants. • Defining Variables Operationally - explaining how to measure a variable in an experiment. • Describing Relationships Between Variables - explain relationships between variables in an experiment such as between the independent and dependant variables plus the standard of comparison. • Designing Investigations - designing an experiment by identifying materials and describing appropriate steps in a procedure to test a hypothesis. • Experimenting - carrying out an experiment by carefully following directions of the procedure so the results can be verified by repeating the procedure several times. • Acquiring Data - collecting qualitative and quantitative data as observations and measurements. • Organizing Data in Tables and Graphs - making data tables and graphs for data collected. • Analyzing Investigations and Their Data - interpreting data statistically, identifying human mistakes and experimental errors, evaluating the hypothesis, formulating conclusions, and recommending further testing where necessary. • Understanding Cause and Effect Relationships - what caused what to happen and why. • Formulating Models - recognizing patterns in data and making comparisons to familiar objects or ideas.
CELLS
The cell is the functional basic unit of life. It was discovered by Robert Hooke and is the functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. Some organisms, such as most bacteria, are unicellular (consist of a single cell). Other organisms, such as humans, are multicellular. (Humans have about 100 trillion or 1014 cells; a typical cell size is 10 µm; a typical cell mass is 1 nanogram. The largest cells are about 135 µm in the anterior horn in the spinal cord while granule cells in the cerebellum, the smallest, can be some 4 µm and the
longest cell can reach from the toe to the lower brain stem (Pseudounipolar cells).[2]) The largest known cells are unfertilised ostrich egg cells which weigh 3.3 pounds In 1835, before the final cell theory was developed, Jan Evangelista Purkyně observed small "granules" while looking at the plant tissue through a microscope. The cell theory, first developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann, states that all organisms are composed of one or more cells, that all cells come from preexisting cells, that vital functions of an organism occur within cells, and that all cells contain the hereditary information necessary for regulating cell functions and for transmitting information to the next generation of cells. The word cell comes from the Latin cellula, meaning, a small room. The descriptive term for the smallest living biological structure was coined by Robert Hooke in a book he published in 1665 when he compared the cork cells he saw through his microscope to the small rooms monks lived in. The cell is one of the most basic units of life. There are millions of different types of cells. There are cells that are organisms onto themselves, such as microscopic amoeba and bacteria cells. And there are cells that only function when part of a larger organism, such as the cells that make up your body. The cell is the smallest unit of life in our bodies. In the body, there are brain cells, skin cells, liver cells, stomach cells, and the list goes on. All of these cells have unique functions and features. And all have some recognizable similarities. All cells have a 'skin', called the plasma membrane, protecting it from the outside environment. The cell membrane regulates the movement of water, nutrients and wastes into and out of the cell. Inside of the cell membrane are the working parts of the cell. At the center of the cell is the cell nucleus. The cell nucleus contains the cell's DNA, the genetic code that coordinates protein synthesis. In addition to the nucleus, there are many organelles inside of the cell - small structures that help carry out the day-to-day operations of the cell. One important cellular organelle is the ribosome. Ribosomes participate in protein synthesis. The transcription phase of protein synthesis takes places in the cell nucleus. After this step is complete, the mRNA leaves the nucleus and travels to the cell's ribosomes, where translation occurs. Another important cellular organelle is the mitochondrion. Mitochondria (many mitochondrion) are often referred to as the power plants of the cell because many of the reactions that produce energy take place in mitochondria. Also important in the life of a cell are the lysosomes. Lysosomes are organelles that contain enzymes that aid in the digestion of nutrient molecules and other materials. Below is a labelled diagram of a cell to help you identify some of these structures.
There are many different types of cells. One major difference in cells occurs between plant cells and animal cells. While both plant and animal cells contain the structures discussed above, plant cells have some additional specialized structures. Many animals have skeletons to give their body structure and support. Plants do not have a skeleton for support and yet plants don't just flop over in a big spongy mess. This is because of a unique cellular structure called the cell wall. The cell wall is a rigid structure outside of the cell membrane composed mainly of the polysaccharide cellulose. As pictured at left, the cell wall gives the plant cell a defined shape which helps support individual parts of plants. In addition to the cell wall, plant cells contain an organelle called the chloroplast. The chloroplast allow plants to harvest energy from sunlight. Specialized pigments in the chloroplast (including the common green pigment chlorophyll) absorb sunlight and use this energy to complete the chemical reaction: 6 CO2 + 6 H2O + energy (from sunlight) later use. Organisms contain many different types of cells that perform many different functions. In the next lesson, we will examine how individual cells come together to form larger structures in the human body. C6H12O6 + 6 O2 In this way, plant cells manufacture glucose and other carbohydrates that they can store for
TISSUES
Tissue is a cellular organizational level intermediate between cells and a complete organism. Hence, a tissue is an ensemble of cells, not necessarily identical, but from the same origin, that together carry out a specific function. Organs are then formed by the functional grouping together of multiple tissues.
A layer or group of cells that collectively perform a specific function forms tissues. These are the main types of tissues found body functions.
Tissues are composed of groups or layers of cells, which perform a collectively specific
in
the and
human their
function. Different types of tissues have different structures that are specific to their function. Tissues can be held together by a sticky coating called an „extracellular matrix‟ or the matrix may weave the cells of tissues together. The Latin word for tissue is derived from the verb
texere, “to weave”.
These are the major tissue types in the human body: Connective Epithelial Muscular Nervous system Lymphatic
Connective Tissue Connective tissue is made up of cells and protein fibers and provides support for other body tissues. The main proteins in connective tissue are collagen and elastin. There are five types of connective tissue. They are: Loose connective tissue: including adipose tissue (fat storage) Dense connective tissue Bone Blood Cartilage
Epithelial Tissue Epithelial tissue, often called epithelium, is comprised of tightly packed cells, arranged to form layers. Epithelium provides many functions, including absorption, excretion, protection, reproduction, secretion and sensory reception. Epithelial cells are constantly renewing and replacing the dead or inactive cells. The two main epithelial tissue types are called a carcinoma. The study of or, tissue in is known as histology tools for connection tissues which and last in are tissue with the is lining and glandular. You can develop colorectal cancer in both of them. Cancer of epithelial tissue is
disease, histopathology. The classical studying block in paraffin
embedded and then sectioned, the histological microscope. decades, stain, In the optical of electron the couple
developments
microscopy, immunofluorescence, and the use of frozen tissue sections have enhanced the detail that can be observed in tissues. With these tools, the classical appearances of tissues can be examined in health and disease, enabling considerable refinement of clinical diagnosis and prognosis.
ORGANS
In biology and (Latin: anatomy, an
organ ὄργανον
organum,
"organ,
"instrument, tool", from Greek organon, instrument, tool" is a collection of tissues joined in structural unit to serve a common function. Usually there is a main tissue and
sporadic tissues. The main tissue
is the one that is unique for the specific organ. For example, main tissue in the heart is the myocardium, while sporadic are the nerves, blood, connective.
ORGAN SYSTEMS
List of major mammalian organ systems There are eleven major organ systems found in mammals. Mammals such as humans have a variety of organ systems. These specific systems are also widely studied in human anatomy. Circulatory system: pumping and channeling blood to and from the body and lungs with heart, blood and blood vessels. Digestive system: digestion and processing food with salivary glands, esophagus, stomach, liver, gallbladder, pancreas, intestines, rectum and anus. Endocrine system: communication within the body using hormones made by endocrine glands such as the hypothalamus, pituitary or pituitary gland, pineal body or pineal gland, thyroid, parathyroids and adrenals, i.e., adrenal glands. Excretory system: kidneys, ureters, bladder and urethra involved in fluid balance, electrolyte balance and excretion of urine. Integumentary system: skin, hair and nails. Lymphatic system: structures involved in the transfer of lymph between tissues and the blood stream, the lymph and the nodes and vessels that transport it including the Immune system: defending against disease-causing agents with leukocytes, tonsils, adenoids, thymus and spleen. Muscular system: movement with muscles. Nervous system: collecting, transferring and processing information with brain, spinal
cord, peripheral nerves and nerves. Reproductive system: the sex organs, such as ovaries, fallopian tubes, uterus, vagina, mammary glands, testes, vas deferens, seminal vesicles, prostate and penis. Respiratory system: the organs used for breathing, the pharynx, larynx, trachea, bronchi, lungs and diaphragm. Skeletal system: structural support and protection with bones, cartilage, ligaments and tendons External features Common names of well known parts of the human body, from top to bottom: Skin
Head – Forehead – Eye – Ear – Nose – Mouth – Tongue – Teeth – Jaw – Face – Cheek – Chin Neck – Throat – Adam's apple – Shoulders Arm – Elbow – Wrist – Hand – Fingers – Thumb Spine – Chest – Breast – Ribcage Abdomen – Belly button – Sex organs (Penis/Scrotum or Clitoris/Vagina) – Rectum – Anus Hip – Buttocks – Leg – Thigh – Knee – Calf – Heel – Ankle – Foot – Toes
Internal organs Common names of internal organs (in alphabetical order):
Adrenal glands – Appendix – Bladder – Brain – Duodenum – Gall bladder – Heart – Intestines – Kidney –Liver– Lungs – Ovaries – Pancreas – Parathyroid gland – Pituitary gland – Prostate gland – Spleen – Stomach – Thymus gland – Thyroid gland – Testicles – Womb.
Top 10 Useless Organs
10 - Plica Semilunaris (3rd eyelid) - You may not know it, but you have a third eyelid. Pull open the two more noticeable eyelids and take a look - it's located right in the corner by the tear duct. The third eyelid is left over from what's known as a "nictitating membrane," which is still present in animals like chickens, lizards and sharks 9 - Body Hair - No doubt we were once hairier. Up until about 3 million years ago, we were covered with it. But by the time Homo erectus arrived, the ability to sweat meant we could shed our wooly ways. 8 – Sinuses - Doctors don't really know much about sinuses, only that we have a lot of them. Possibilities for their function range from insulating our eyes to changing the pitch and tone of our voice. 7 – Adenoids - Adenoids trap bacteria, but they're also prone to swelling and infection. Just ask any 7-year-old. Luckily, our adenoids shrink with age and are often removed, along with... 6 – Tonsils - Also prone to swelling and infection. If you have them by your 30s, it's almost an accomplishment 5 – Coccyx - More useful as a game-winning Scrabble word than part of the anatomy, the coccyx, or tailbone, is several fused vertebrae left over from the olden days when we had tails. 4- Erector Pili - When were hairier the erector pili made the hairs stand on end when we needed to appear bigger and scarier. Now, it just gives us goose bumps. 3 - Wisdom Teeth - Back in the day, when we ate mammoth meat off the bone and didn't floss afterward, our teeth tended to fall out. Therefore, when those reserve molars, aka "wisdom teeth," came in they were welcomed. Nowadays, fluoride and dental plans have just made them a huge pain 2 – Appendix - Darwin claimed the appendix was useful for digestion during our early plant-eating years; it's dwindled down to little since we started eating more digestible foods. 1- Male Nipples - Because, they don't secrete milk at all, just all for show and nothing more.
