Controlling heart rate Flashcards
What the two parts that make up the Autonomic Nervous System?
Sympathetic Nervous System and Parasympathetic nervous system
The Sympathetic and Parasympathetic Nervous System are said to be ___?
Antagonistic
Define myogenic
Contractions begin within the muscles
In relation to contractions, the heart is said to be _____
Myogenic
Where do the hearts contractions begin?
In the sinoatrial node SAN
Describe the process of the heart contacting
A wave of electrical energy from SAN across both atria
Causes atria to contract
Atrioventricular septum prevents wave crossing to ventricles
Wave enters Atrioventricular node AVN and after a short delay, this coveys the wave between the ventricles via the Purkyne tissue
What is the average human resting heart rate?
70 bpm
What controls changes to the heart rate?
medulla oblongata
Where does the impluses come from to increase the heart rate?
SAN via the sympatheic Nervous system
Where does the impluses come from to decrease the heart rate?
SAN via the parasympatheic Nervous system
Explain how physical excercise can lead to an increased heart rate and why
Increased muscular activity
more CO2 produced by tissue from increased respiration
which lowers blood pH
chemical receptor in carotid arteries increase freq. of impulses to the medulla oblongata
centre in MO increase heart rate by increasing speed and freq. of impluses to SAN via the sympatheic Nervous system
SAN increases heart rate
Increased blood flow removes CO2 after
pH can increase and Co2 returned 2 normal
How does the heart detect the pH of the Blood?
Chemoreceptors in carotid arteries walls
How does the heart detect the pressure of the Blood?
pressue receptors in carotid arteries and arota walls
What occurs when the presure is higher than normal?
Increase implsued to medulla oblongata when rate decreases mo sends impulses via parasympathetic nervous system 2 SAN
