Tyagi, Avantika 1st period - Unit 2 Part B

Organizing the Human Body, Cells, Cell Division & Genetics, Cell Processes and Conditions, Tissues, Organs, Body Systems,

Organizing the Human Body:

• Cell - Basic structural unit of the body

• Tissue - Combination of similar cells

• Organ - Collection of tissues working together to form a particular function

• Body system - Consists of a group of organs that work together to perform a specific function

• Organism - A life form made up of interdependent parts (cells, tissue, organs, and body systems) that work together to maintain life

NOTE: Homeostasis

At all levels, the goal of these elements is to maintain homeostasis, a stable internal environment of physiological balance, despite changes inside or outside the body.

Examples are temperature control, regulation of blood glucose, and maintaining a fluid balance.

Cells:

Starting from below:

Cytology

The study of the formation, structure, and function of cells.

Organelles

Cells contain organelles, specialized structures that enable specific functions.

Cell membrane, or Plasma membrane

Surrounds every cell, separating it from the external environment. The membrane is considered a selective semipermeable membrane since it determines what enters and leaves the cell.

Nucleus: Part 1

Controls the cell. It is responsible for the main function and reproduction of the cell.

Nucleus: Part 2

• The nucleus of every human cell (except for the sex cells, egg and sperm) contains 46 chromosomes arranged in 23 pairs, 22 of which are identical. The final pair of chromosomes are the XX and XY chromosomes that determine a person’s biological sex.

• Each chromosome contains deoxyribonucleic acid (DNA), which is responsible for each person’s unique genetic makeup.

Cytoplasm

Semifluid material between the nucleus and cell membrane. This is where chemical reactions occur.

Electrolytes

Compounds made up of charged particles called ions. Ions conduct electrical currents in water or cytoplasm.

Cations

Positively-charged ions that create acids.

Anions

Negatively charged ions that create bases. Bases react with acids to form salts.

The pH

The pH of a fluid measures the presence of acids and bases. Cells and tissues function at different pH levels and can’t function properly if a normal pH balance is not maintained.

Muscle cells

Long, slender cells within muscle tissue. They allow muscles to contract and relax.

Epithelial cells

Flat, square cells covering the skin and lining the digestive tract and hollow organs.

Fat cells

Contain large, empty spaces to store fat.

Nerve cells

Tend to be long with fibrous extensions to carry nerve impulses.

Blood cells

Vary in size and shape according to their function.

Sex cells:

The ovum (female sex cell) is the largest cell in the body. The sperm (male sex cell) is the smallest.

Cell Division and Genetics

Starting from below:

NOTE: Cell Division

Cell division allows for (1) growth and development of cells and (2) replacement of old, dead, or damaged cells.

Mitosis and Meiosis

Most cells divide through mitosis, resulting in two genetically identical daughter cells. Meiosis is a type of cell division that produces sex cells (gametes), such as sperm and eggs, with half the usual number of chromosomes.

Genetics

The study of ways in which genes are transferred from individuals to their offspring and the role genes play in the health of the offspring.

Genetic disorders, or hereditary disorders

Diseases or conditions caused by a defective gene. They may be present at birth or may not be apparent until later in life.

Cell Processes and Conditions

Starting from below:

Anabolism

A building-up process in which energy combines smaller units into molecules, or groups of two or more atoms that chemically bond together with specific properties.

Aplasia

Condition in which a cell, tissue, or organ does not grow or develop normally

Carcinogenesis

Formation of development of cancer

Endocytosis

Process in which substances are brought inside a cell

Eukaryotic

Having a clearly defined nucleus

Exocytosis

Process in which substances are transported outside of a cell

Histogenesis

Production of tissues

Hypertonic

Having a greater pressure or concentration in a solution than a cell, causing water to flow out of the cell, resulting in cellular shrinking

Hypotonic

Having a lower pressure or concentration in solute than a cell, causing water to flow into the cell, resulting in cellular swelling

Isotonic

Having equal pressure or concentration inside and outside of a cell

Lysosomes

Organelles that destroy pathogens and non-functional cells

Prokaryotic

No clearly defined nucleus

Tissues

Starting from below:

Tissue

A group of similar cells working together to perform a specific function. Histology is the study of the structure and function of tissues.

Histology

Histology is the study of the structure and function of tissues.

Biopsy

Allows a provider to remove a small piece of tissue, a portion of an organ, or an entire organ for microscopic examination.

Pathologist

A physician who specializes in the study of disease, examines the tissue or sections of the organ under a microscope.

1. Epithelial tissue

Forms the skin covering the surface of the body, lines the internal organs, and makes up certain glands. Epithelial tissues are typically characterized by the number of cell layers within the tissue and the shape of the tissue’s cells.

Simple epithelium

Tissue with one layer of cells

Stratified epithelium

Tissue with more than one layer

Squamous

Flat shape

Cuboidal

Cube-shaped

Columnar

Cells shaped like columns

2. Connective tissue

Supports and connects organs and other body tissues.

Dense connective tissue

Bone, cartilage

Loose connective tissue

Nerve cells, blood vessels

Adipose tissue

Also referred to as fat, provide heat-retaining insulation

Liquid connective tissue

Blood, lymph

3. Muscle tissue

contracts (shortens) to produce bodily movements. There are three major types of muscle tissue.

Skeletal muscle, or voluntary muscle

It is attached to bones. These muscles work with the musculoskeletal system to generate movement at will.

Cardiac muscle

Only found in the heart and is responsible for the pumping function of the heart.

Smooth muscle, or visceral muscle, or involuntary muscle

Lines the walls of hollow organs, like those in the digestive tract.These muscles can’t be consciously controlled.

Peristalsis

Results from smooth muscles alternating contraction and stretching motions, and it helps move substances along a pathway, such as digested food through the intestines.

Nervous tissue

Makes up the nervous system and is made of neurons, which receive and conduct electrochemical impulses between the brain and other parts of the body.

Organs

Structures composed of several kinds of tissues that work together to perform a specific function. Examples: Heart, lungs, stomach, brain

Body Systems

Starting from below:

NOTE:

There are eleven major body systems.

Body Systems

Made groups of organs that work together to perform complex functions and maintain life. The body systems work together to maintain homeostasis, or the body’s state of balance. None of the body systems function in isolation; they are interdependent. When one body system fails, others are also affected, creating a cascade of problems throughout the body.

Integumentary System:

Skin, hair, nails, sweat and oil glands

● Protects the body by acting as a physical barrier against pathogens, harmful chemicals, and ultraviolet rays of the sun

● Regulates body temperature and fluid balance

● Produces vitamin D, which is necessary for calcium absorption

● Provides sensory information to the brain about touch, pressure, pain, and temperature provides

Skeletal System:

Bones, joints, cartilage, ligaments, tendons

● Provides support and shape for the body

● Protects internal organs and tissues

● Produces blood cells

● Stores calcium and minerals

Muscular System:

Muscles

• Allows voluntary and involuntary body movement

• Produces heat through energy generated by muscles

Nervous System:

Brain, spinal cord, nerves

● Transmits messages about sensory stimuli between the brain and other parts of the body

Endocrine System:

Hypothalamus, pituitary gland, thyroid, thalamus, adrenal glands, pancreas, gonads (ovaries in females, testes in males)

● Produces hormones and regulates body functions, including metabolism, mood, growth and development of cells and tissues, and reproductive development and function

Respiratory System:

Nasal cavity, pharynx, larynx, trachea, bronchi, lungs

● Delivers life-sustaining oxygen to body tissues and organs

● Expels carbon dioxide

● Filters airborne pollutants and some microorganisms

● Regulates pH (acid-base) levels in the body

Cardiovascular (“Circulatory”) System:

Heart, blood vessels

● Pumps blood containing oxygen and nutrients throughout the body

● Carries carbon dioxide to the lungs and other chemical wastes to the kidneys and lungs for elimination

Lymphatic (“Immune”) System:

Spleen, lymph nodes, vessels, and tissues, thymus, bone marrow

● Protects the body from microorganisms that cause disease

● Maintains a proper balance of blood and lymphatic fluid in the body

Digestive System:

Mouth, esophagus, stomach, small intestine, large intestine, gallbladder, liver, appendix, rectum, anus

● Responsible for the ingestion (taking in), breakdown, and absorption of nutrients

● Removes solid waste products from the body as feces

Urinary system:

Kidneys, ureters, bladder, urethra

● Filters blood to remove waste products

● Regulates electrolytes and fluid balance in the body

Reproductive System:

Female - mammary glands, fallopian tubes, uterus, vagina, Male - penis, testes, scrotum, prostate gland

● Allow human beings to produce offspring