Cirvello #1: Introduction Flashcards
Cellular Physiology
Examines cellular processes. (Growth, division, metabolism, differentiation, excretion, and absorption.)
Systematic Physiology
Examines organ system processes (breathing, the beating of the heart, the movement of food through the intestines, or moving our arms and legs).
Neurophysiology
Examines nervous system processes (seeing, hearing, touch, language, memory, and abstract thought).
Cardiovascular Physiology
Examines heart and blood vessel processes (blood pressure and blood flow).
Pathology
Examines all aspects of disease, with an emphasis on the cause and development of abnormal conditions, as well as the structural and functional changes resulting from disease.
Many diseases, or pathophysiologies, arise from an inability to maintain homeostasis (like diabetes), from a flaw in the normal cell-cell communication pathways (cancer), or from a structural alteration that disrupts the expected function (sickle cell anemia).
-itis
Inflammation
Supine
A person laying on his or her back.
L. supinus. to lay.
Prone
Person laying on the stomach.
L. pronus, sloping.
Serous Membrane
The interiors of the trunk cavities are lined with serous membranes, which are doubled walled structures. The serous membranes are named by the tissues with which they’re associated with.
Serous membranes provide for physical contact between organs and a cavity in such a way that organs can move.
Contains fluid that acts as a lubricant between the two membranes.
Visceral Membrane
Has direct contact with the organ of interest.
Parietal Membrane
Has contact with the wall of the cavity.
Thoracic Cavity Serous Membranes
Contain 3 distinct serous membranes.
The pericardial (L. peri, around; cardi, the heart) membrane surrounds the heart and made up of the visceral and parietal pericardium.
The visceral pericardium is in direct contact with the heart.
The parietal pericardium is in direct contact with the thoracic cavity.
Space between the two membranes is filled with pericardial fluid that reduces friction as the heart beats. The pericardium helps to anchor the heart in place, preventing excessive movement of the heart in the chest. It protects heart from infections and tumors that develop in, and may spread from, adjacent tissues and may also help keep the heart from enlarging.
Mesenteries
Modified sheets of membranes that the peritoneum forms.
Mesenteries holds the organs of the digestive tract in position and convey nerves, blood vessels, and lymphatic ducts to organs.
Negative Feedback Loops
Changes in physiologic processes oppose, or negate, the original stimulus. In response, the receptors send messages to the CNS which will execute something to maintain the internal condition due to an external change.
It is possible for homeostatic mechanisms to have different levels of resolution and control. The rate at which the variable is corrected back to the set point (known as gain) is also controllable.
Feed-Forward System
Many feedback loops seem to anticipate changes in physiologic systems and start corrective action before there are significant swings in physiologic variables. These types of systems don’t respond to feedback info in either a negative or positive way.
A good example is found when a hungry person smells food and salivates in response. The formation of saliva does not increase or decrease hunger pains.
Feed-foward systems anticipate events and prepare for them.
Positive Feedback Loops
Not as common. A sensor detects changes in a physiologic variable, which then activates an effector cell, which causes the variable to move farther away from a set point (in a positive direction).
More difficult to control and causes physiologic variables to change from the set point.
Dilation of Cervix During Birth
The dilation of the cervix during birth is under the control of positive feedback loop and then stops as soon as baby is born before uterus is damaged.
Blood Clots
Formation of blood clots is caused by a positive feedback loop. In this case, it’s more important to rapidly change blood conditions so that a clot forms in response to an injury, because it’s more dangerous to bleed uncontrollably.
However, blood clots must be prevented from occurring randomly throughout the body. To prevent unwanted clots, several systems limit their formation to only areas of damage. Positive feedback loops are important in how the nervous system controls and communicates with other cells.
Brest Feeding
A positive feedback system. As baby feeds on mother’s breast, oxytocin ejects more milk, and continues to do so as baby keeps feeding.
Cell-To-Cell Communication
How body acts to limit changes in key physiologic variables depends on this. Any coordinated activity requires the exchange of communication between different components so that they act in unison for the common good.
Two main types of pathways. Nervous and hormonal.
Works because it is specific and cells respond only to the correct message, sensitive so that only very low levels of the message are needed, and accurate so that the message is correctly understood.
Mechanisms That Regulate Homeostasis
Two general mechanisms regulate homeostasis:
- Autoregulation or intrinsic regulation, an automatic response by a cell, tissue, organ or organ system to a change in its environment.
- Extrinsic regulation, changes regulated by the nervous system or endocrine system.
(a) The nervous system responds to external stimuli (e.g. a hot stove) with short-term nerve responses.
(b) The endocrine system responds to internal conditions with long-term chemical controls – hormones.
A homeostatic regulatory mechanism consists of 3 parts:
- Receptors, sensors that respond to a stimulus.
- The control center, receives information from sensors and sends out commands.
- Effectors, the cell or organ that responds to the control center.
