Topic Test T2 Wk2 (digestion & excretion) Flashcards Preview

Human Biology Year 11 > Topic Test T2 Wk2 (digestion & excretion) > Flashcards

Flashcards in Topic Test T2 Wk2 (digestion & excretion) Deck (42):
1

Digestive System Functions

Ingestion of food
Absorption of digested food
Mechanical digestion
Chemical digestion
Elimination of waste

2

Mouth

Mechanical Digestion: teeth and tongue undertake chewing
Chemical Digestion: salivary amylase breaks down carbohydrates

3

Swallowing

Tongue forms food into bolus
Peristalsis carries bolus into stomach through waves of muscle contraction

4

Stomach

Mechanical Digestion: muscular churning producing chyme
Chemical Digestion: protein into amino acids through gastric juices containing gastric protease
Leaves stomach via pyloric sphincter

5

Duodenum

Mechanical Digestion: contraction
Mechanical Digestion: lipid emulsification by bile (breaking up)
Chemical Digestion: through pancreatic amylase, pancreatic lipase and protease

6

Small Intestine

Contain finger like projections called villi
Increases surface area for nutrient absorption

7

Enzymes in SI

Intestinal Amylase
Intestinal Lipase
Intestinal Protease

8

Absorption in SI

Glucose, amino acids, water, minerals are absorbed into blood capillaries
Fatty acids and glycerol absorbed into lacteals in the lymphatic system

9

Large Intestine

No villi, no enzymes
Water and vitamin absorption

10

Liver

Produces bile
Bile is stored in gall bladder and carried to duodenum

11

Pancreas

Secretes pancreatic juice into duodenum
Controls blood insulin levels

12

Rectum and Anus

Faecal storage and defecation
Anal sphincter muscles open allowing waste to be expelled

13

Mechanical Digestion

Breakdown of food into smaller particles without changing its chemical makeup

14

Teeth

4x incisors
2x canines
4x premolars
6x molars

15

Incisors

Chisel shaped for cutting and biting

16

Canines

Cone shaped for tearing

17

Premolars and molars

Broad crown with rounded cusps, for grinding and crushing

18

Chemical Digestion

Breakdown of large molecules into smaller molecules with a different chemical structure
Involves enzyme

19

Breakdown of carbohydrates

In the mouth
Broken down by salivary amylase
Then broken down in the duodenum by pancreatic amylase
Then broken down by intestinal amylase

20

Breakdown of protein

Broken down in stomach by gastric protease
Continues in duodenum with pancreatic protease breaking dipeptides to peptides

21

Breakdown of lipids

First emulsified by bile salts in the duodenum via mechanical
Broken down by intestinal lipases

22

Villi

Finger like projections
Hold microvilli
Create large surface area

23

What is a Absorbed?

The glucose and amino acids pass into blood capillary of villi
They go to liver in hepatic portal vein and continue in circulatory system
Fatty acids and glycerol go into lymphatic vessels in villi called lacteals

24

Water Absorption

Occurs in colon (large intestine)

25

Defacation

Undigested waste is stored in rectum until sphincter opens and is expelled through anus

26

Excretion

Removal of harmful byproducts of metabolism by the body

27

Kidney has....

3 layers cortex, medulla and renal pelvis

28

Cortex

Dark brown outer layer
Contains renal columns which provide into medulla

29

Medulla

Darker middle layer
Contains triangular structures called renal pyramids

30

Renal Pelvis

Edge contains cup like extensions called major calyces
Each subs divides into several
Each surround the tip of the renal pyramid

31

Nephron

The functional unit of the kidney is the nephron
Produce urine and filter blood
Begins in cortex

32

Renal Corpuscle

Consists of a double walled cup that surrounds a knot of capillaries

33

Loop of Henle

Connected to proximal convoluted tubule is a hairpin loop which passes into a pyramid in medulla
Tube heading down- descending limb of loop of henle
Tube heading up- ascending limb

34

Distal Convoluted tubule

Twisted tube attached to ascending limb of loop of henle

35

Blood Supply

Blood enters kidney through renal artery, branches into arterioles into glomerulus
Blood leaves glomerulus via afferent arteriole

36

Three stages of urine production

Filtration
Reabsorption
Secretion

37

Filtration

1. Blood enters kidney via renal artery
2. Afferent arterioles lead to capillaries of glomerulus
3. Water and dissolved substances filter out of the blood into glomerular capsule
4. Fluid carried via efferent arteriole to proximal convoluted tube

38

Reabsorption

Substances move fork renal tubules to capillaries
Water, glucose, sodium ions etc are reabsorbed
Reabsorption begins in proximal convoluted tubules and continues in loop of henle etc

39

Secretion

Hydrogen ions, potassium ions, ammonia and certain drugs out of the blood into kidney tubules.
Where they eventually are eliminated in urine
(Occurs in distal convoluted tubules)

40

Excretion

Urine is carried to calyces to ureters to the bladder and the exterior bus urethra

41

Factors affecting urine composition

Exercise
Environment
Diet
Alcohol

42

Deamination

Stripping of nitrogen from amino acids and nitrogen bases
Conversion of excess amino acids into urea
Nitrogen is toxic to human body must be removed
Occurs in liver