<< Chapter < Page Chapter >> Page >
By the end of this section, you will be able to:
  • Discuss the mechanisms involved in the neural regulation of vascular homeostasis
  • Describe the contribution of a variety of hormones to the renal regulation of blood pressure
  • Identify the effects of exercise on vascular homeostasis
  • Discuss how hypertension, hemorrhage, and circulatory shock affect vascular health

In order to maintain homeostasis in the cardiovascular system and provide adequate blood to the tissues, blood flow must be redirected continually to the tissues as they become more active. In a very real sense, the cardiovascular system engages in resource allocation, because there is not enough blood flow to distribute blood equally to all tissues simultaneously. For example, when an individual is exercising, more blood will be directed to skeletal muscles, the heart, and the lungs. Following a meal, more blood is directed to the digestive system. Only the brain receives a more or less constant supply of blood whether you are active, resting, thinking, or engaged in any other activity.

[link] provides the distribution of systemic blood at rest and during exercise. Although most of the data appears logical, the values for the distribution of blood to the integument may seem surprising. During exercise, the body distributes more blood to the body surface where it can dissipate the excess heat generated by increased activity into the environment.

Systemic Blood Flow During Rest, Mild Exercise, and Maximal Exercise in a Healthy Young Individual
Organ Resting
(mL/min)
Mild exercise
(mL/min)
Maximal exercise
(mL/min)
Skeletal muscle 1200 4500 12,500
Heart 250 350 750
Brain 750 750 750
Integument 500 1500 1900
Kidney 1100 900 600
Gastrointestinal 1400 1100 600
Others
(i.e., liver, spleen)
600 400 400
Total 5800 9500 17,500

Three homeostatic mechanisms ensure adequate blood flow, blood pressure, distribution, and ultimately perfusion: neural, endocrine, and autoregulatory mechanisms. They are summarized in [link] .

Summary of factors maintaining vascular homeostasis

This flowchart shows the various factors that control the flow of blood. The top panel focuses on autoregulation, and the bottom panel focuses on neural and endocrine mechanisms.
Adequate blood flow, blood pressure, distribution, and perfusion involve autoregulatory, neural, and endocrine mechanisms.

Neural regulation

The nervous system plays a critical role in the regulation of vascular homeostasis. The primary regulatory sites include the cardiovascular centers in the brain that control both cardiac and vascular functions. In addition, more generalized neural responses from the limbic system and the autonomic nervous system are factors.

The cardiovascular centers in the brain

Neurological regulation of blood pressure and flow depends on the cardiovascular centers located in the medulla oblongata. This cluster of neurons responds to changes in blood pressure as well as blood concentrations of oxygen, carbon dioxide, and hydrogen ions. The cardiovascular center contains three distinct paired components:

  • The cardioaccelerator centers stimulate cardiac function by regulating heart rate and stroke volume via sympathetic stimulation from the cardiac accelerator nerve.
  • The cardioinhibitor centers slow cardiac function by decreasing heart rate and stroke volume via parasympathetic stimulation from the vagus nerve.
  • The vasomotor centers control vessel tone or contraction of the smooth muscle in the tunica media. Changes in diameter affect peripheral resistance, pressure, and flow, which affect cardiac output. The majority of these neurons act via the release of the neurotransmitter norepinephrine from sympathetic neurons.

Questions & Answers

what is hypoxia
Akas Reply
I guess it's low supply the oxygen to the tissues
famuyiwa
yup
Natalie
A condition in which tissues (especially the blood) are deprived of an adequate supply of oxygen
Panthera
hanifa pia uko hapa
Panthera
where is present Glenoid Cavity ?
A- Reply
what is the muscular tissue
Md Reply
muscular tissue is a type of tissue that provide to help in cotraction to aur body.
A-
What's the difference in epithelial, connective, muscular and muscle tissue
Gifty
and it's similarities
Gifty
what is limb bone
Akshu Reply
this are bone attaching or joining to the axial bone.axial bone including skull,vertebrate and ribcage
Eliasi
how many bones make up the skull?
Matthew
22 bones
Husna
22bones
Bhanu
where is present Glenoid cavity ?
A-
how many bone in skull
Md
Explain the stages of mitosis and cell division
Bella Reply
systems of human body
Udezue Reply
define lymphatic system And give the composition of lymphatic fluid
sakshi Reply
the network of vessels through which lymphatic drains From the tissue into blood.lymph contain variety of substance like salts, glucose, proteins and fatsand water, white blood cells
Bhanu
yeah
Hassan
what is lymphatic system
Adie Reply
the network of vessels through which lymph drains from tissue into the blood
Bhanu
to describe the boundaries of four cavity
Pius Reply
homeostatic variables such as body temperature fluctuates within a normal range around the set point, or ideal, for a given homeostatic condition. for example, 98.6°F is a set point for body temperature. The response of the effector determines whether or not the homeostatic variable remains in the n
Chidinma Reply
why rbc is biconcave?
Sudhakar Reply
to carry oxygen easily
anwaar
What part of the brain controls the body temp
Ridwan
hypothalamus
JAYESH
what are epithelial tissues
Sachibu Reply
epithelial tissue that cover overall parts of the body and it's free from blood and nerves
Bhanu
Epithelial tissues are composed of cells laid out in sheets with strong cell-to-cell attachments.
Duah
Epithelial tissues perform a variety of functions that include; protection, secretion, filtration, diffusion, absorption, etc.
Duah
what control the flow of the blood ?
Donkor Reply
the pumping action of the heart
Holly
what is bony promises on the human body
Kelly Reply
what is the bony promises on human body
Kelly
what are bony prominences on human body
Kelly
support of the body
Bhanu
what are the characteristics of blood
yeboah Reply
they are red in colour
Tawoi
why blood is red in color?
Sudhakar
blood is red because it contains hemoglobin
Abena

Get the best Anatomy & Physiology course in your pocket!





Source:  OpenStax, Anatomy & Physiology. OpenStax CNX. Feb 04, 2016 Download for free at http://legacy.cnx.org/content/col11496/1.8
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Anatomy & Physiology' conversation and receive update notifications?

Ask