Muscle & Nervous tissue

Question 1

• comes in three forms;
• all are very cellular in nature, highly vascularized and function in some form of movement.
• has the ability to convert chemical energy into mechanical energy to produce movement, maintain posture, regulate organ volume, produce heat, and generate force.
• The three types are (1) skeletal muscle is striated and under voluntary control, (2) cardiac also striated but involuntary, and (3) smooth muscle which has no visible striations and is not under voluntary control.

Answer 1

Muscle tissue

Question 2

• is wrapped in connective tissue and is usually attached to bones.
• When the term “flesh” is used, it is referring mainly to this muscle.
• sacromeres
• functions in voluntary movement and heat production; facial expressions; voluntary control; locomotion
• Please note that muscle cells are called fibers because of their elongated appearance. However, muscle fibers are true, living cells with a full compliment of organelles. They are not to be confused with the non-living extracellular fibers secreted by connective tissue cells.

Answer 2

Skeletal muscle

Question 3

• As we will learn in more detail when we consider the muscular system, muscles are made up of thousands of long cylindrical cells. The cytoplasm is packed with myofibrils made up mainly of the contractile proteins actin and myosin. These are arranged into structural/functional units called ____. This gives the cells a striated appearance under the microscope. Each cell is multinucleated, however the nuclei lie just underneath the plasma membrane because of all the myofibrils occupying the cytoplasm.

Answer 3

sarcomeres

Question 4

• is also striated, but it has some major structural and functional differences when compared to skeletal muscle.
• First, __ __ cells are not long, mulitinucleated cylinders, but are branched and contain only 1-2 nuclei that are located in the center of the cell.
• are connected to one another by unique structures called intercalated discs.
• FUNCTION: As it contracts, it propels blood into the circulation; involuntary control
• location: Walls of the heart

Answer 4

Cardiac muscle

Question 5

• These connections are specialized to hold the muscle cells together, and to pass electrical stimuli from one cell to the next.
• The ___contain anchoring or tight junctions to keep the cardiac cells from pulling apart when the heart beats, and gap junctions that allow muscle action potentials to pass from one cardiac muscle cell to another. When a single cardiac muscle fiber in the network is stimulated, the stimulus is passed to all the fibers causing them to contract. This is very different from skeletal muscle in which each cell receives its own nerve stimulus and can contract independently of other cells.

Answer 5

intercalated discs

Question 6

• is found in the walls of hollow organs other than the heart.
• gets its name because no striations are visible giving the cytoplasm a smooth appearance. The cytoplasm of the cells does contain contractile proteins, but these are not arranged into sarcomeres.
• Individual __ __ cells are spindle-shaped and contain only a single, centrally located nucleus.
• Contraction is relatively slow compared to striated muscle, but the cells can sustain the contraction for much longer.
• can shorten and stretch to a greater extent than skeletal muscle. Just think about the amount of stretch the uterus undergoes during pregnancy.
• FUNCTION: moves food, urine, and reproductive tract secretions; controls diameter of respiratory passageways; regulates diameter of blood vessels
• is located in the walls of blood and lymph vessels, hollow viscera, and bronchioles (air ways leading to lungs).
• also makes up the arrector pili muscles which are the small muscles at the base of hair follicles that make them stand up when you are cold. The tiny muscles around the iris which adjusts the pupil according to focal distance and light levels, and that cause the lens of the eye to bulge or flatten when focusing on near or distant objects are comprised of smooth muscle.

Answer 6

Smooth muscle

Question 7

• makes up the entire nervous system which includes the brain, spinal cord, peripheral nerves, and sensory receptors.
• It is made up of two major categories of cells. The neurons are the cells capable of responding to stimuli and are able to generate and propagate nerve impulses known as action potentials.
• The second category includes a diverse assemblage of supportive cells called the neuroglia (which means neuron glue).
• The nervous system which is the body’s primary means of controlling and integrating incoming information and responses. Thus, different components of __ ___ have the ability to detect, analyze, and transmit information as variable as temperature, pain, light, sounds, stretching of your stomach, chemical changes in the blood, tension in tendons, stretch in muscles, etc. Acting together as an organ system, nervous tissue is the body’s primary means of controlling and integrating incoming sensory information and formulating the appropriate outgoing response. Thus, the three major functions of __ __ are, sensory, motor and integration.

Answer 7

nervous tissue

Question 8

• ___ are considered the structural/functional units of the nervous system because they are the ones that generate and send impulses.
• Most ___ are characterized by having processes that can be very long.

Answer 8

neurons

Question 9

• Processes that receive information are called __

Answer 9

dendrites

Question 10

the message-sending process is called an __ .

Answer 10

axon

Question 11

The cell body contains the nucleus and other organelles. In this photomicrograph, the large orange-staining cells are the neurons and the tiny orange dots are the nuclei of neuroglial cells of various types.

Answer 11

facts..