Biology 28.1

Epitelial tissues

Consists of protective sheets of tightly packed cells connected by special junctions. The skin and the membranes that line the stomach, the lungs, and other organs are epithelial tissues.

Apoptosis

A type of cell death in which the cell uses specialized cellular machinery to kill itself. Like when your hand is first formed, it resembles a mitten, then turns into a hand. The cells between the fingers dies, allowing the individual fingers to develop.

Skeletal muscle

Align in bands of orderly rows and contain many nuclei. They are responsible for nearly all voluntary muscle movements, such as lifting your foot to kick a ball.

Muscle tissue

Capable of contracting to produce movement. The human body contains skeletal, cardiac, and smooth muscle tissues.

Embryonic stem cells

Cells produced during the first few divisions of the zygote. Have the potential to become any type of specialized cell in the body.

Humans

Collections of specialized cells that work together.

Sperm cells

Develop whiplike tails that enable them to swim.

Organs

Different types of tissue that function together form an organ.

Specialized cells

Each type of specialized cell has a particular structure and a chemical make up that enable it to perform a specific task.

Cells lining the gut

Elongated and tightly packed to provide more surface area for the absorption of nutrients.

Four general types of tissues

Epithelial, connective, muscle, nervous

Zygote

Formed by the union of an egg and sperm. All cells come from the zygote. Zygote divides and differentiates into more than 200 types of different human cells.

Organ

Group of different types of tissues that work together to perform a specific function or related functions.

Tissue

Groups of similar cells that work together to perform a specialized function.

Tissues

Groups of similar cells that work together to perform a specialized function.

Mucus cells

Helps to trap foreign particles and protect the lungs from pathogens such as bacteria and viruses.

Cell specializiation

Involves two main steps: determination and differentiation.

Multicellular organisms

Made up of different cells that all have different functions.

Determination

Most stem cells become committed to develop into only one type of cell.

Cells after determination

Once a cell is committed to becoming a specialized cell, it will develop into only that type of cell. A cell committed to becoming a neuron can only become a neuron, even if transplanted into another part of the body. During normal development, determination cannot be reversed.

Lungs

Organs comprised of all four types of tissues. Muscle and connective tissue expand and contract the lungs. Nervous tissue sends and receives messages that help regulate gas exchange in the lungs and the rate at which a person breathes. Epithelial tissue forms the inner lining of the lungs.

Organ systems

Perform the most complex activities in the body.

Determination

Process by which stem cells become committed to develop into only one type of cell.

Cells in the lungs

Responsible for the exchange of gases.

Connective tissues

Serves to support, bind together, and protect other tissues and organs. Tendons, ligaments, bone, and cartilage are all connective tissues.

Smooth muscle cells

Shorter than skeletal cells and have only one nucleus. They perform involuntary movements, such as raising the hair on your arms and legs.

Differentiation

The process by which committed cells acquire the structures and functions of highly specialized cells.

Differentiation

The process by which committed cells acquire the structures and functions of highly specialized cells. It occurs because specific genes in each cell are turned on and off in a complex, regulated pattern. The different structures of these specialized cells allow them to perform specific functions within the body.

The function of muscle cells

To produce movement by contracting and relaxing.

Nervous tissue

Transmits and receives impulses in response to stimuli, processes information, and regulates the bodies response to its environment.

Organ system

Two or more organs that work in a coordinated way to carry out similar functions.

Organ systems

Two or more organs working in a coordinated way. The organ system that allows you to breathe-not only the lungs, but the sinuses, the nasal passages, the pharynx, and the larynx.