Human Biology - Ventilation And Heart Rate

Front 1

What is the DRG?

Back 1

Dorsal Respiratory Group.
It initiates inspiration.

Front 2

What is the VRG?

Back 2

Ventral Respiratory Group. Activated during exercise.
Stimulates internal intercostals and abdominal muscles.
Both muscles are inactive during normal breathing.

Front 3

What pulls the ribs upwards during inspiration?

Back 3

Intercostal nerve → external intercostal muscles contract → pulling ribs upwards

Front 4

What moves the diaphrham down?

Back 4

Phrenic nerve → diaphragm contracts → moves downwards

Front 5

What happens during normal expiration?

Back 5

Stretch receptors are found within smooth muscles of bronchi and bronchioles
They are stimulated and send impulses via vagus nerve
Vagus nerve inhibits the DRG and stops inspiration
Diaphragm moves upwards and external intercostal muscles relax

Front 6

What happens during forced expiration (excerise)?

Back 6

Stimulation of VRG
Abdominal muscles contract, pushing diaphragm upwards
Internal intercostal muscles contract, pulling ribs downward
Results in more powerful and faster expiration

Front 7

How is respiration monitored?

Back 7

By brainstem respiratory centres.

Front 8

What does respiration do?

Back 8

Maintains pH, oxygen, and carbon dioxide in blood within normal limits.

Front 9

What monitors the breathing rate?

Back 9

Blood CO2 and O2 levels

Front 10

How is more CO2 produced?

Back 10

More CO2 is produced by removing hydrogen ions
This increases blood pH

Front 11

What are Chemoreceptors for?

Back 11

Monitor pH and CO2 levels
Send impulses to the medulla

Front 12

Where are Chemorecetors located?

Back 12

Located in the aorta (aortic bodies) and common carotid arteries (carotid bodies)

Front 13

What do the Aortic bodies monitor?

Back 13

CO2 and O2 levels, and Blood Pressure but NOT pH!

Front 14

What do the Carotid bodies monitor?

Back 14

CO2 and O2 levels, and pH

Front 15

What is the Autonomic Nervous system made up of?

Back 15

Parasympathetic and Sympathetic

Front 16

What does the Parasympathetic do?

Back 16

Stimulates vagus nerve causing decrease in heart rate.

Front 17

What does the Sympathetic do?

Back 17

Increases heart rate.

Front 18

Where is the Cardiac inhibitory centre found?

Back 18

In the medulla of the brain.

Front 19

What is this connected to?

Back 19

Connected to the heart by parasympathetic fibres found within the vagus nerve.

Front 20

When stimulated what is released?

Back 20

ACh which decreases the heart rate.

Front 21

What connects the Cardiac accelerating centre to the heart?

Back 21

Sympathetic fibres

Front 22

Cardiac accelerating centre releases which hormone?

Back 22

Trigger the release of noreadrenaline.
This ↑heart rate and ↑strength of contractions.

Front 23

What monitor blood pressure?

Back 23

Baroreceptors near aorta and carotid arteries.

Front 24

Give the definition of stroke volume:

Back 24

The volume of blood pumped by one ventricle during one beat.

Front 25

What is the cardiac output?

Back 25

Cardiac Output = Stroke Volume x Heart Rate

Front 26

What are the two main energy sources during excersise?

Back 26

Glucose and Triglycerides.

Front 27

Where is glucose stored?

Back 27

As glycogen in liver.

Front 28

Where are Triglycerides stored?

Back 28

Stored in adipose tissue

Front 29

When are triglcyerides and glucose broken down?

Back 29

Triglycerides: Long-term exercise (Takes longer to break down).

Glucose: Short-term excersise (Quickly broken down)

Front 30

What is aerobis respiration?

Back 30

Complete oxidation of an organic substrate to CO2 and H2O using free O2.

Front 31

What happens when more O2 required than available?

Back 31

Anaerobic respiration starts.

Front 32

How is ATP produced during anaerobic respiration?

Back 32

Glucose is converted to lactate.

Front 33

What is lactic acid?

Back 33

Another name for lactate.

Front 34

What does lactic acid do?

Back 34

Diffuses into blood and lowers its pH.
Accumulates in muscles causing muscle fatigue and cramps.

Front 35

What happens to lactate?

Back 35

Most is re-oxidised to CO2 and H2O once oxygen is available again.
Some is converted into glycogen, glucose, and proteins.
Some is excreted in urine and sweat.

Front 36

Why is ATP is useful as an immediate energy source?

Back 36

Energy release only involves a single reaction
Energy released in small quantities
Easily moved around inside cells, but cannot pass through cell membranes

Front 37

How many subunits does Haemoglobin contain?

Back 37

4

Front 38

Name the features of red blood cells that allow them to transport O2 more efficiently:

Back 38

Larger surface area to volume ratio for diffusion.
Absence of other organelles so more room for haemoglobin.