Other Tissues

Muscle and Nerve Tissue

Below are images of two other basic tissue types: Three muscle tissues, Skeletal, Cardiac and Smooth, as well as Nerve which rounds out the basic examination of tissues.

Skeletal muscle is a voluntary muscle which attaches to the skeleton and causes body movements. Also known as Striated muscle, these cells tend to be long and cylindrical, with several nuclei per cell. The striations come from bands of protein which act to cause a shortening of the cell, and contraction of the muscle as a whole. They also have large numbers of mitochondria to supply the cell with lots of energy.

Cardiac muscle is the muscle found in the heart and is responsible for pumping of the blood. Cardiac muscle cels are also cylindrical, but shorter than skeletal cells, with only one nucleus. These striated cells are often branched and connected to adjoining cells by an intercalated disc, which assists the coordination of contractions of cardiac muscle cells.

Smooth muscle forms the walls of most hollow organs (except the heart), and is also found in the skin and eyes. These cells are responsible for many functions, such as moving food through the digestive system and the emptying of the bladder or adjusting the size of the eye's iris. These cells are tapered at the ends, giving them a spindle appearence. They have one nucleus and are not striated.

Nervous tissue forms the brain, spinal cord, and nerves. It is responsible for coordinating and controlling many bodily functions. Nerve tissue consists of neurons, or nerve cells, which is responsible for the action potential cpnduction (the electric impulse nerves use to communicate). Neurons consist of the cell body, which does basic cell activities, and dendrites (which receive impulses) and axons (one per cell, conducting impulses away from cell body). Neuroglia are support cells. Glial cells include the following cells:

Astrocytes, which secrete chemicals which help maintain the blood/brain barrier. Microglia, which are small phagocytic cells which float around the tissue consuming pathogens and waste. Ependymal cells line the open spaces within the brain and spinal cord producing CSF. They possess cilia which help with the circulation of CSF.

Two cell types wrap themselves around axons, speeeding up impulses by forming myelin. Oligodendrocytes are found around axons in the CNS, while Schwann cells are found in the PNS. Schwann cells are unique because they provide a pathway for the regeneration of neurons in the PNS so that lost connections can be restored. Unfortunately, Oligodendrocytes do not provide this for cells in the CNS, thus damage there is perminant.

	Skeletal muscle is a voluntary muscle which attaches to the skeleton and causes body movements. Also known as Striated muscle, these cells tend to be long and cylindrical, with several nuclei per cell. The striations come from bands of protein which act to cause a shortening of the cell, and contraction of the muscle as a whole. They also have large numbers of mitochondria to supply the cell with lots of energy.
	Cardiac muscle is the muscle found in the heart and is responsible for pumping of the blood. Cardiac muscle cels are also cylindrical, but shorter than skeletal cells, with only one nucleus. These striated cells are often branched and connected to adjoining cells by an intercalated disc, which assists the coordination of contractions of cardiac muscle cells.
	Smooth muscle forms the walls of most hollow organs (except the heart), and is also found in the skin and eyes. These cells are responsible for many functions, such as moving food through the digestive system and the emptying of the bladder or adjusting the size of the eye's iris. These cells are tapered at the ends, giving them a spindle appearence. They have one nucleus and are not striated.

	Nervous tissue forms the brain, spinal cord, and nerves. It is responsible for coordinating and controlling many bodily functions. Nerve tissue consists of neurons, or nerve cells, which is responsible for the action potential cpnduction (the electric impulse nerves use to communicate). Neurons consist of the cell body, which does basic cell activities, and dendrites (which receive impulses) and axons (one per cell, conducting impulses away from cell body). Neuroglia are support cells. Glial cells include the following cells:
	Astrocytes, which secrete chemicals which help maintain the blood/brain barrier. Microglia, which are small phagocytic cells which float around the tissue consuming pathogens and waste. Ependymal cells line the open spaces within the brain and spinal cord producing CSF. They possess cilia which help with the circulation of CSF. Two cell types wrap themselves around axons, speeeding up impulses by forming myelin. Oligodendrocytes are found around axons in the CNS, while Schwann cells are found in the PNS. Schwann cells are unique because they provide a pathway for the regeneration of neurons in the PNS so that lost connections can be restored. Unfortunately, Oligodendrocytes do not provide this for cells in the CNS, thus damage there is perminant.