Autonomic Nervous System and CVP function Flashcards
What are the two main divisions of the autonomic nervous system involved in controlling blood pressure?
Sympathetic and parasympathetic nervous systems.
How does the sympathetic nervous system affect blood pressure?
It increases heart rate (positive chronotropy) and contractility (positive inotropy), leading to increased cardiac output and higher blood pressure.
What is the role of the parasympathetic nervous system in blood pressure regulation?
It decreases heart rate and contractility, which lowers stroke volume and cardiac output, resulting in decreased blood pressure.
What is the primary function of the cardiovascular system?
To provide perfusion by delivering oxygenated blood to tissues.
What are the determinants of blood pressure?
Cardiac output (stroke volume and heart rate), peripheral vascular resistance, blood volume, blood viscosity, and elasticity of blood vessel walls.
What is the relationship between stroke volume and blood pressure?
An increase in stroke volume leads to an increase in blood pressure.
How does peripheral vascular resistance affect blood pressure?
Higher peripheral vascular resistance (vasoconstriction) increases blood pressure, while lower resistance (vasodilation) decreases blood pressure.
What centers in the medulla control the sympathetic and parasympathetic nervous systems?
The cardiac accelerator center (activates sympathetic) and the cardiac inhibitory center (activates parasympathetic).
Where are baroreceptors located, and what is their function?
Baroreceptors are located in the carotid sinus and aortic arch, and they sense blood pressure changes.
What happens to baroreceptor firing when blood pressure increases?
The firing rate of baroreceptors increases with higher blood pressure, which sends signals to the central nervous system to adjust blood pressure accordingly.
Describe the response of the autonomic nervous system to decreased blood pressure.
Baroreceptor firing decreases, leading to reduced parasympathetic activity (increased heart rate) and increased sympathetic activity (vasoconstriction), raising blood pressure.
Describe the response of the autonomic nervous system to increased blood pressure.
Baroreceptor firing increases, activating the parasympathetic system (decreasing heart rate and contractility) and inhibiting the sympathetic system (reducing peripheral resistance), lowering blood pressure.
What is perfusion, and why is it important?
Perfusion is the delivery of oxygenated blood to tissues; it’s essential for maintaining cellular function and overall health.
What is the role of the vagus nerve in heart regulation?
The vagus nerve activates the parasympathetic nervous system, which decreases heart rate and contractility.
What is the normal body temperature range for humans?
97 to 99 degrees Fahrenheit (approximately 36.1 to 37.2 degrees Celsius).
Why is it crucial to maintain body temperature within the normal range?
It ensures that normal metabolism occurs and that the body functions adequately.
What happens to the body if thermoregulation fails?
The body may not function properly and can ultimately lead to expiration.
What are thermoreceptors and what is their role?
Thermoreceptors sense changes in body temperature and compare it to the set point in the hypothalamus.
Where are thermoreceptors located in the body?
In the skin and the preoptic area of the hypothalamus.
What is the function of warm-sensitive neurons in the hypothalamus?
They activate the parasympathetic system to cause vasodilation and activate sweat glands, promoting heat dissipation.
How do cold-sensitive neurons in the hypothalamus respond to decreased body temperature?
They activate the sympathetic system to cause vasoconstriction, minimizing heat loss.
Describe the response when body temperature increases above the hypothalamic set point.
The heat-loss center is activated, leading to dilation of skin blood vessels and activation of sweat glands, which dissipates heat.
What occurs when body temperature decreases below the hypothalamic set point?
The heat-promoting center is activated, causing constriction of skin blood vessels and activation of skeletal muscles to generate heat (shivering).
What are the two main centers in the hypothalamus that regulate body temperature?
The heat-loss center and the heat-promoting center.
How does the body respond to fever?
The body temperature rises above normal, and mechanisms for heat dissipation may be impaired, leading to decreased overall function.
What role does the preoptic area of the hypothalamus play in thermoregulation?
It contains thermoreceptors that help compare the body’s temperature with the hypothalamic set point.
What physiological changes occur during shivering?
Skeletal muscles are activated to generate heat, increasing body temperature back to normal.
What mechanism helps to cool the body down during excessive heat?
Sweating and vasodilation of blood vessels help dissipate heat.
What is the primary function of energy systems in the body?
To provide ATP for daily activities and physiological processes.
What are the two main factors involved in energy homeostasis?
Energy intake (food consumption) and energy expenditure (physiological processes and exercise).
Which two systems primarily control energy metabolism?
Hormonal systems and neural systems.
How does glucose play a role in energy metabolism?
Glucose is a key determinant of energy intake and output, influencing feeding behavior and energy expenditure.
What happens to glucose after food is ingested?
It is absorbed into the GI tract, enters circulation, and is sent to the liver for glucose production.
What role do incretins play in glucose metabolism?
Incretins stimulate the release of insulin in two phases, suppressing glucose production and inhibiting glucagon release.
What is the traditional view of food intake regulation?
Controlled primarily by glucoreceptors comparing arterial and venous blood glucose levels.
What is the contemporary view of energy balance in the body?
A complex network involving multiple systems, particularly the arcuate nucleus of the hypothalamus.
What are orexigenic neurons, and what do they do?
Appetite stimulants in the arcuate nucleus, including Neuropeptide Y (NPY) and Agouti-related Peptide (AgRP).
What are anorexigenic neurons and their function?
Appetite suppressants controlled by Proopiomelanocortin (POMC), leading to reduced feeding behavior.
Which hormones influence the activity of orexigenic and anorexigenic neurons?
Leptin, PYY, ghrelin, and insulin.
What role does leptin play in energy metabolism?
It reduces feeding behavior and helps inhibit obesity.
How does exercise affect appetite and energy metabolism?
Acute exercise can temporarily suppress appetite and decrease ghrelin levels while increasing PYY levels.
What is the effect of exercise on insulin resistance?
Exercise reduces insulin resistance, improving glucose metabolism.
What is the role of Brain-Derived Neurotrophic Factor (BDNF) in exercise?
BDNF plays a crucial role in memory and learning, which is enhanced by exercise.
How does aerobic exercise impact motor learning, according to research?
Aerobic exercise post-practice can improve performance and reduce error in motor tasks over time.
Why is it important for physical therapists to understand energy metabolism?
They can educate and modify environmental and individual factors affecting patients’ energy intake and expenditure.
What metabolic disorders can arise from energy metabolism failures?
Obesity and type II diabetes mellitus.
