Limbic system and emotions - Brain Functions

 Limbic system and emotions

The olfactory cortex and certain deep cortical regions and nuclei of the cerebrum and the diencephalon are grouped together under the title limbic (lim′ bik; a boundary) system (figure 8.33). The limbic system influences long-term declarative memory, emo-tions, visceral responses to emotions, motivation, and mood. A major source of sensory input to the limbic system is the olfac-tory nerves. The limbic system responds to olfactory stimulation by initiating responses necessary for survival, such as hunger and thirst. The limbic system is connected to, and functionally associated with, the hypothalamus. Lesions in the limbic sys-tem can result in voracious appetite, increased (often perverse) sexual activity, and docility (including loss of normal fear and anger responses).



Comments

Post a Comment

Popular posts from this blog

Effect of Exercise on Breathing

Image
  Effect Of Exercise On Breathing The mechanisms by which breathing is regulated during exercise are controversial, and no single factor can account for all the observed responses. Breathing during exercise can be divided into two phases: 1.                         Breathing increases abruptly.  At the onset of exercise,the rate of breathing immediately increases. This initial increase can be as much as 50% of the total increase that  will occur.   The immediate increase occurs too quickly to be explained by changes in metabolism or blood gases. As axons pass from the motor cortex of the cerebrum through the motor pathways, numerous collateral fibers project to the respiratory center. During exercise, action potentials in the motor pathways stimulate skeletal muscle contractions, and action potentials in the collateral fibers stimulate the respiratory ce...
Read more

Cardiac Cycle

Image
  CARDIAC CYCLE The right and left halves of the heart can be viewed as two separate pumps. Each pump consists of a primer pump—the atrium—and a power pump—the ventricle. The atria act as primer pumps because they complete the filling of the ventricles with blood, and the ventricles act as power pumps because they produce the major force that causes blood to flow through the pulmonary and systemic circulations. The term  cardiac cycle  refers to the repeti-tive pumping process that begins with the onset of cardiac muscle contraction and ends with the beginning of the next contraction (figure 12.17). Pressure changes produced within the heart chambers as a result of cardiac muscle contraction move blood from areas of higher pressure to areas of lower pressure.  Atrial systole  (sis′t ō -l ē ; a contracting) refers to contraction ofthe two atria.  Ventricular systole  refers to contraction of the two ventricles.  Atrial diastole  (d ı̄ -as′ t...
Read more

Heart Sounds

Image
  HEART SOUNDS The  stethoscope  (steth′ ̄o -sk̄o p;  stetho,  the chest) was originally developed to listen to the sounds of the lungs and heart and is now used to listen to other sounds of the body as well. Figure 12.19 shows the sites in the thorax where the heart sounds can best be heard with a stethoscope. There are two main heart sounds. The first heart sound can be represented by the syllable  lubb,  and the second heart sound can be represented by  dupp.  The first heart sound has a lower pitch than the second. The first heart sound occurs at the beginning of ventricular systole and results from clo-sure of the AV valves (see figure 12.17, step 3, and figure 12.18). The second heart sound occurs at the beginning of ventricular diastole and results from closure of the semilunar valves (see figure 12.17, step 5, and figure 12.18). The valves usually do not make sounds when they open.   Clinically, ventricular systole occurs between...
Read more