Vertebrates II: Fetal Pig Dissection (cont.) Circulatory, Urinary, and Reproductive Systems; Sheep Heart Dissection

Question 1

What is the function of the circulatory system?

Answer 1

transports materials throughout an animal’s body in a fluid called blood

Question 2

What are the vessels that blood is pumped through in decreasing diameter? (oxygenated)

Answer 2

arteries, arterioles and capillaries

Question 3

at the capillary bed, how are materials transported (two ways)

Answer 3

1) actively transported across the endothelium

2) simply diffuse into the interstitial fluid along a concentration gradient

Question 4

As blood leaves the capillaries, what vessels does it travel though (increasing diameter)

Answer 4

venules then veins

Question 5

how are blood vessels characterized?

Answer 5

by the direction in which they carry materials

A Away (arteries and arterioles) from the heart

Question 6

What is the evolutionary reason for a 4 chambered heart?

Answer 6

birds and mammals (warm blooded/endotherms) have high metabolic demands

endotherms expend 10 times the energy that cold blooded (ectotherms) do

Question 7

What are the two separate and independent circuits (sequestration of oxygenated blood from deoxygenated blood)

Answer 7

1) pulmonary circuit (to lungs)

2) systemic (to body)

Question 8

Blood flow through the heart from an arbitrary starting point (starting from the vena cava)

Answer 8

1) vena cava
2) right atrium
3) tricuspid valve
4) right ventricle
5) pulmonary semilunar valve
6) right and left pulmonary arteries —-> arterioles
7) lungs (capillary beds)

co2 diffuses out, o2 in and hemoglobin binds o2

8) right and left pulmonary veins (oxygenated blood now)
9) left atrium
10) bicuspid valve
11) left ventricle (largest and strongest muscle of the heart)
12) aorta
13) aortic semilunar valve
14) body

Question 9

what is the largest artery in the mammalian body?

Answer 9

the aorta

Question 10

Where does the main branch of the aorta travel? What is its function?

Answer 10

the main branch travels posteriorly along the dorsal midline of the body

supplies the organs in the abdomen (via capillaries) and tissues of the hind legs (via smaller arteries and arterioles)

Question 11

what supplies the heart muscle itself with oxygenated blood

Answer 11

coronary arteries

Question 12

How many capillary beds are there in each circuit? What are portal systems?

Answer 12

There is one capillary bed system in each circuit, one pulmonary system and the other for the organs and tissues of the systemic system

However, there are specialized branches in the systemic circulation called portal systems! (PORTAL SYSTEMS ARE THE SPECIALIZED BRANCHES IN THE SYSTEMIC SYSTEM)

Question 13

What is the function of the lymphatic system?

Answer 13

draining fluid from the interstitial spaces of the body into the veins of the systemic circulatory system

Question 14

fetus vs adult circulation (what differs)

Answer 14

oxygen content found in each vessel

Question 15

How does the liver eliminate wastes? What other systems eliminate waste?

Answer 15

The liver eliminates waste through bile pigments

carbon dioxide is expelled from the lungs

salts, metal ions and fats can be eliminated through gastrointestinal tract

but, the bulk of the waste is removed by the urinary system!

Question 16

What is the urinary system comprised of

Answer 16

1) pair of kidneys
2) components of urinary tract

a) ureters(tubes that drain the kidneys) that lead to
b) urinary bladder (stores waste)
c) urethra (tube where waste exits)

Question 17

Functions (goals) of the urinary system? (4)

Answer 17

1) eliminate physiological wastes
2) osmoregulation
3) maintain blood pressure
4) detoxification and nutrient conservation

Question 18

where does meiotic division occur in males and females

Answer 18

meiotic division occurs in specialized cells in the gonads

testes in the male

ovaries in the female

Question 19

components of the reproductive system

Answer 19

1) gonads (tested m./ovaries f.)
2) ducts that receive or transport gametes for fertilization
3) glands that secrete fluids into the duct
4) specialized organs (genitalia) for transfer (male) or reception (female)

Question 20

What is it called when the anterior vena cava split into two main branches?

Answer 20

These branches are called the brachiocephalic veins

Each branch subdivides into two more vessels (4 branches total); one bifurcates into the major vessels of the chest and forelegs, the subclavian and brachial veins, and the other bifurcates and travels up into the neck forming the internal and external jugular veins.

Question 21

brachiocephalic veins vs brachiocephalic artery

Answer 21

the brachiocephalic vein branches off of the vena cava

the brachiocephalic artery branches off of the aortic arch (the first large vessel to branch off of the aortic arch)

Question 22

aorta and the blood vessels that emanate (two)

Answer 22

1) the brachiocephalic artery

branches off into the right subclavian artery which subdivides further to the right thorax, neck and forelimb

2) the left subclavian artery

subdivides and supplies left thorax, neck and forelimb

Question 23

how does the aorta curve

Answer 23

once the brachiocephalic arteries are cut, the heart and lungs can be lifted so that you can see how the aorta curves dorsoposteriorly.

Question 24

location of the esophagus

Answer 24

esophagus lies dorsal to the trachea and it overlies the aorta as they both pass through the diaphragm into the abdominal cavity

Question 25

Location of the aorta and posterior vena cava in the abdominal cavity

Answer 25

aorta and posterior vena cava run side by side just ventral to the vertebral column. cushioned in a layer of fat and **covered by the parietal peritoneum**, thus** they lie outside all of the visceral organs except the excretory organs**. As you will see shortly, the kidneys and their associated vessels are also retroperitoneal.

Question 26

outer vs inner region of endocrine cells in the adrenal gland

Answer 26

outer secretes around 20 different hormones inner secretes epinephrine and norepinephrine

Question 27

what is the first large artery to branch from the aorta after it passes the diaphragm

Answer 27

celiac trunk supplies blood to the stomach, liver, gallbladder, pancreas and spleen

Question 28

what is the next major artery (posterior to the celiac artery) that branches off of the aorta? What organs does it supply?

Answer 28

the mesenteric artery supplies the small intestine and most of the large intestine

Question 29

branches off of the aorta traveling posteriorly

Answer 29

1) celiac trunk 2) anterior mesenteric artery 3) adrenolumbar arteries (supplies blood to the adrenal glands) 4) renal arteries (kidneys) 5) genital arteries (reproductive tissues) 6) second posterior mesenteric artery (remainer of the large intestine) ends in 3 vessels two common iliac arteries (hindlimbs) -branch off further. One branch is the femoral artery sacral artery (tail)

Question 30

what is the function of the umbilical arteries in fetal pigs located at the terminus of the aorta

Answer 30

carry oxygen depleted blood **away** from the fetus to the placenta

Question 31

tracing the veins that connect to the vena cava starting at the posterior position in the abdomen

Answer 31

femoral, iliac, sacral, right genital, renal, and adrenolumbar veins follow similar paths to their corresponding arteries. left genital vein joins the left renal vein and does not connect directly to the vena cava.

Question 32

where does the blood that leaves the gastrointestinal tract go

Answer 32

enters the vena cava through the hepatic portal system

Question 33

blood leaving the organs in the abdominal cavity

Answer 33

capillaries of spleen and stomach to the gastrosplenic vein small and large intensive to the anterior and posterior mesenteric veins. anterior and posterior mesenteric veins merge to form one large mesenteric vein. gastrosplenic and large mesenteric vein merge to form hepatic portal vein hepatic portal vein brings blood to sinusoids (exchange vessels like capillaries)

Question 34

where does the liver receive blood from?

Answer 34

hepatic portal vein hepatic arteries (contains small branches of the bile duct)

Question 35

what is the function of hepatocytes (liver cells)

Answer 35

absorb material carried in blood’s plasma and secrete substances carried by sinusoids

Question 36

what is the location of the adrenal gland?

Answer 36

anterior position of kidney more specifically, medial edge of the anterior part of the kidney

Question 37

3 different regions of the kidney

Answer 37

1) renal cortex (outermost, solid colored mass that encircles the renal medulla) 2) renal medulla (layer of fibrous branching tissue that surround renal pelvis) 3) renal pelvis (central chamber that collects urine produced by nephrons (functional units of the kidney))

Question 38

what do the ureters do?

Answer 38

drain urine from the renal pelvis of each kidney

Question 39

what is the bladder? what is the difference in shape between adult and fetus (pig)

Answer 39

stores urine spherical in adults long tapered sac (called the **allantoic bladder** )in fetuses that extends past the umbilical arteries. Allantoic stalk removed urine and carries it to the placenta