CARDIOVASCULAR REGULATIONByDr.H.Gusbakti,MSc,PKK,AIFMProfessor
of Physiology
Homeostatic mechanisms regulate cardiovascular activity to
ensure that tissue perfusion, or blood flow through tissues, meets
the demand for oxygen and nutrients. The three variable factors
are: (1) Cardiac output, (2) peripheral resistance, and (3) blood
pressure.
The goal of cardiovascular regulation is to ensure that these
blood flow changes occur (1) at an appropriate time, (2) in the
right area, and (3) without drastically changing blood pressure and
blood flow to vital organs.
Factors involved in the regulation of cardiovascular function
include local factors, neural mechanisms, and endocrine
mechanisms.
A. Local factors: Local factors change the pattern of blood flow
within capillary beds in response to chemical changes in
interstitial fluids. Autoregulation occurs at the tissue level when
each tissue controls the amount of its blood supply according to
its need through controlling the tone of the blood vessel supplying
it. If autoregulation fails to normalize conditions at the tissue
level, neural mechanisms and endocrine factors are activated.
B. Neural mechanisms. Neural mechanisms respond to changes in
arterial pressure or blood gas levels at specific sites. When those
changes occur, the cardiovascular centers of the autonomic nervous
system adjust cardiac output and peripheral resistance to maintain
blood pressure and ensure adequate blood flow.
C. Endocrine mechanisms. The endocrine system releases hormones
that enhance short-term adjustments and direct long-term changes in
cardiovascular performance.
