A&P II Final

Where is the respiratory center located?

In the medulla oblongata

What is the respiratory center in the medulla oblongata?

Neurons that control day-to-day breathing

What does the basic breathing rhythm?

The ventral respiratory group

What muscles does the ventral respiratory group interact with?

They contact muscles around the thoracic cavity

When do excitatory impulses from the ventral respiratory group occur?

When you breathe in

When do excitatory impulses from the ventral respiratory group disappear?

When you exhale

What is the typical breathing rate?

About 10 to 15 breaths per minute

What does the dorsal respiratory group do?

Sends sensory info to the ventral respiratory group to alter the breathing rate or depth

What two things does the dorsal respiratory group sense?

1) Chemical levels

2) Stretch

Why does the dorsal respiratory group sense stretch?

To stop the lungs from stretching too much so that they don’t pop

What chemical is the driving force for breathing rate?

Carbon dioxide

What is hypercapnia?

Elevated carbon dioxide levels in the body

What does hypercapnia typically happen from?

Metabolic buildup

How does the breathing frequency change in response to hypercapnia?

It increases to expel carbon dioxide

What is apnea?

A disruption in breathing due to very low carbon dioxide levels in the body

Why does the body stop breathing when carbon dioxide levels are very low?

The body wants to retain carbon dioxide

Do carbon dioxide levels and blood pH increase outside of homeostatic ranges during exercise?

No

* Hypercapnia does not occur during exercise

What sends impulses to the medulla oblongata about the composition in the body?

The hypothalamus

What does the hypothalamus cause when it anticipates that you are going to exercise?

It increases your breathing rate to stay ahead of your body’s needs

Why is there a drop in breathing rate when you stop exercising?

The anticipatory response goes away

How long does it take for breathing frequency to go back to baseline levels?

2 to 3 minutes

What is hyperventilation?

Really fast breathing

Why do you hyperventilate?

From emotions, medical conditions, etc.

What would happen if you hyperventilate for too long?

You would pass out from protecting blood flow to the brain

Why does blood flow to the brain stop if you hyperventilate?

Vasoconstriction stops blood flow to the brain to maintain carbon dioxide levels in the body

What are the 2 parts of the lymphatic system?

1) Lymphatic vessels

2) Lymphatic organs

Where are lymphatic vessels located?

They’re embedded in circulatory capillaries

How does fluid enter lymph vessels?

As fluid leaves the arterial side of blood vessels due to hydrostatic pressure, lymphatic vessels pull some interstitial fluid into the lymph vessels

What 2 things does lymph do?

1) Helps with the accumulation of fluid in tissues

2) Drains into lymph organs to check the fluid

How does lymph help with the accumulation of fluid in tissues?

It’s a drainage system

What happens to lymph in lymph organs?

It is checked for debris, foreign antigens, or bacteria

When is fluid not released from lymph organs?

Fluid isn’t released if something in the fluid is abnormal

Why do lymph nodes swell when you’re sick?

Because fluid is retained in them

What are lymph nodes?

Pockets of tissue in lymph organs

What type of cells do lymph nodes have a lot of?

B-cells

What do B-cells make?

Lots of different antibodies

What happens to any fluid that is deemed good?

It is released back into the circulatory, venous system

What is lymph?

Fluid that has been collected by lymphatic vessels

How does lymph flow?

ALWAYS in 1 direction back to the heart

What 2 traits of lymph vessels allow them to be a drainage system?

1) Their anatomy allows them to be really permeable

2) How their endothelial cells interact

3) Little collagen filaments anchor lymphatic vessels

Why is it important that lymph vessels are really permeable?

You want all the bad debris to enter the lymph vessels, not just the fluid

* They collect protein that left the circulatory system, cancer cells, debris, and antigens

How do endothelial cells interact?

They lie on top of each other to create 1-way valves

* To get in you just press down on the side of the valves

What are lymphatic capillaries called?

Collecting vessels

What do collecting vessels do?

They keep merging to make bigger and bigger collecting vessels until they create the lymphatic trunk

* The lymphatic trunk is the largest in diameter

What does the lymphatic trunk merge into?

The lymph duct

What does the lymph duct do?

It drains back into the veins

What cells do lymph nodes have a lot of?

* B-cells
* T-cells

What do T-cells do?

They monitor antigens

What do T-cells do when they flag an antigen?

They activate B-cells

What is released if an antigen has been encountered before?

Antibodies

What are the most permeable vessel in the body?

Lymph vessels

What are lymphoid cells?

Cells of the lymphatic system

What are lobules?

High concentrations of B-cells

Where are lobules found?

In lymph organs

Are antibodies specific?

Yes, extremely specific

Do you need a lot of B-cells?

Yes, to have a wide range of antibodies

What 2 layers do lymph organs have?

* A cortex layer
* A medulla layer

Which layer of lymph organs is the superficial layer?

The cortex layer

Which layer are B-cell patches a part of?

The medulla layer

Which layer are macrophages a part of?

The cortex

Are macrophages specific?

No

How many vessels lead to lymph structures?

Multiple vessels

How many vessels leave lymph structures?

Only 1 vessel

Why does only 1 vessel leave lymph structures?

* To slow the speed of fluid so it can be checked better
* Fluid can’t escape undetected so all fluid will be scanned

What type of vessels are in lymph structures?

Circulatory vessels

What cells go to lymph structures from the circulatory system to give immunity from the blood?

White blood cells

When does fluid become lymph?

When it enters lymph structures

Where is lymph filtered?

ONLY in lymph nodes

Where are lymph nodes located?

They are scattered throughout the body, specifically where collecting vessels merge into lymph trunks

Are lymph nodes deep or superficial?

Extremely superficial

What are the other three lymph organs?

1) Spleen

2) Thymus

3) Tonsils

What does the spleen do?

It filters blood

What is already present if the spleen finds bacteria in the blood?

An immune response

Where is the thymus located?

In the neck

What does the thymus do?

Allows T-lymphocytes to mature and be activated by sending signals

What do T-lymphocytes do?

Flow through the blood and encounter bacteria by themselves

* They take bacteria to B-cells to activate them

What do you need to activate a B-cell?

A T-cell presenting an antigen

When is the thymus growing quickly?

During the 1st year of life

Why do kids not have good specific immunity during their first year of life?

Because T-cells aren’t mature yet so they can’t activate B-cells yet

Where are tonsils located?

In the back of the oral cavity

* They are the gateway between the oral cavity and the pharynx

Are the tonsils open or closed to the oral cavity?

Open

What is supposed to happen anytime you consume bacteria?

It should go right to the tonsils

What type of cells do the tonsils also need?

T-cells and B-cells

Are the tonsils mature in the 1st year of life?

No

* This is why some kids need to get their tonsils removed because they are constantly enlarged because they can’t handle bacteria yet

What are the 2 types of immune responses?

1) Innate system

2) Adaptive system

Are people born with the innate or adaptive system?

The innate system

What is the innate system composed of?

Physical barriers that are non-specific

When do antigens go from the innate system to the adaptive system?

When the number or size of the antigens is too great for the innate system

What are 2 physical barriers that are part of the innate system?

1) The skin

2) Mucosa membranes

What component of the skin is protective against weak acids?

Keratin

Where are mucosa membranes located?

In the oral cavity, respiratory structures, and digestive structures

What do mucosa membranes do?

Secrete lots of fluid that’s acidic so it kills things

What does the skin secrete?

Things that are good at killing bacteria

Why is mucus sticky?

So it sticks to antigens

What happens to mucus with antigens stuck to it?

Little hairs in the respiratory system move the mucus up the respiratory structures so you cough it up instead of it going into the alveoli

What does the mucus in the digestive structures protect them from?

It protects the stomach from the acid its secreting

What are the innate responses in the blood?

* Macrophages
* Neutrophils
* Eosinophils

Is inflammation an innate response?

Yes

What does inflammation allow your body to do?

Come together to fight an antigen

What happens to cause inflammation?

Damaged tissues start to release chemicals