PHYL 142 Lab Exam #3

What does the digestive system provide the body with?

What does the digestive system provide the body with?

• nutrients

• water

• electrolytes

What does the digestive system do for the body?

eliminates undigested remains as feces

2 processes of the digestive system

• digestion - food break-down

• absorption - nutrient distribution into cells

2 divisions of the digestive system

• alimentary canal - (GI tract)

• accessory digestive organs

alimentary canal (GI tract)

includes the lining from the esophagus to the anal canal

What is the alimentary canal composed of?

4 basic layers or TUNICS:

• mucosa

• submucosa

• muscularis externa

• serosa / adventitia

accessory organs of the digestive system

• teeth

• tongue

• salivary glands

• liver

• gallbladder

• pancreas

mucosa

innermost tunic of the wall that lines the lumen of the digestive tract

submucosa

layer of dense, irregular (loose) connective tissue that supports the mucosa

muscularis externa

muscular wall of the GI tract, deep to the submucosa

serosa/adventitia

outermost (most distant from the lumen) layer of the GI tract

Intrinsic Nervous Plexus

innervates the stomach and enables gut function “gut-brain axis”

Palatine/Lingual tonsils

lymphoid tissues located posteriorly at each sides of the mouth (under the tongue)

tonsilitis

inflamed and enlarged Palatine tonsils

What are tonsils apart of?

the immune system

esophagus/gullet

NO digestion or absorption

What is the sole purpose of the esophagus?

move food to the stomach in wave-like motions

How long is the esophagus in a human?

25 cm long

Where is the stomach located?

located on the left side of the abdominal cavity (hidden by liver and diaphragm)

What part of the stomach is food broken down?

pyloric part

gastric glands

• aids in the pyloric region of the stomach

• secret HCl and hydrolytic enzymes

What does HCl do for the digestive system?

• helps break down protein

• absorb essential nutrients

• control viruses and bacteria

What does hydrolytic enzymes do for the digestive system?

break down other molecules into smaller fragments

mucosal glands

secret mucus to protect stomach from digestive fluids

chyme

processed food that enters the small intestine

small intestine

• where absorption occurs

• completes the digestion process

Brush Border enzymes

hydrolytic enzymes in the microvilli cells that help complete the digestion process

Microvilli

cells that help increase the surface so that it can absorb more nutrients

circular folds

• slow the passage of the partly digested food along the intestines

• afford an increased surface for absorption

Where does majority of absorption occur?

small intestine

appendicitis

removal of the appendix due to inflammation

diarrhea

a result from undigested food before water is absorbed

constipation

results in food remaining in the large intestine for too long where most of the water is reabsorbed

lactose intolerance

the body not generating lactase to digest lactose properly

peristalsis

movement of food from oral cavity to stomach via esophagus

segmentation

movement of chyme in the intestines

catalyst

increases the rate of a chemical reaction without becoming the product

enzyme

ends in “ase”

trypsin

• makes protein digestion possible

• produced in the pancreas

• hydrolyzes protein to become peptide molecules

Gut microbiota

• encompasses all the different microbes in the gut

• very important for overall metabolism

acid-base balance

the body’s pH level in extracellular fluids (input & output)

• important for maintaining normal function of organs

• important for body’s “homeostasis”

pH

determined by the pH (potential of hydrogen) scale

• measures how “acidic or basic” a solution is

Key information about pH scale

• distilled water will always be a neutral aqueous solution

• less than 7 = acidic

• greater than 7 = basic or alkaline

What organ systems utilize acid-base balance?

• cardiovascular system (blood)

• respiratory system (lungs)

• urinary system (kidneys)

carbonic acid-bicarbonate buffer system

most important buffer for maintaining the pH homeostasis of blood

• stabilizes blood to pH of 7.4 +/- 0.02

acid base equation

H20 + CO2 → H2CO3

• water and carbon dioxide forms carbonic acid with the aid of carbonic anhydrase as the catalyst

chloride shift

RBCs exchange HCO3- for Cl

• helps maintain negative charge in RBCs

• may help with binding affinity to oxygen

What is the acid-base mnemonic?

• R - espiratory

• O - ppposite

• M - etabolic

• E - qual

acidosis

state in which there is a failure of ventilation and accumulation of carbon dioxide

• increased PCO2

• increased carbonic acid

• increased H+ = low pH

• increased bicarbonate

• “HYPOVENTILATON”

alkalosis

disease state where the body’s pH is elevated to greater than 7.45

• decreased PCO2

• decreased carbonic acid

• decreased H+ = high pH

• decreased bicarbonate

• “HYPERVENTILATION”

What is the relationship between breathing and blood pH?

reduced respiratory rate will lead to a decreased pH

• the more carbon dioxide is exhaled, the less carbon dioxide is present

kidney

MAJOR HOMEOSTATIC ORGAN

• removes nitrogenous waste

• maintains electrolytes balances

• acid-base balances

• fluid balances

What is a kidney imbalance?

• kidney AGENESIS - born with only 1, other failed to develop

• kidney DYSPLASIA - both present but only ONE is functioning

• surgery - removed to treat disease

may result in DEATH as the worst possible scenario

What are the 5 main structures of the urinary system?

1. Paired Kidneys - filtration = urine

2. Renal Pelvis - collects urine and is funneled into the ureter

3. Ureters - transports urine by peristalsis to the bladder (connects kidney to the bladder)

4. Bladder - temporary storage of urine

5. Urethra - drains bladder

   1. males - 2 functions

   2. females - only excretes urine

perirenal fat capsules

situated near the 12th ribs and supported by fat that prevents infections in surrounding regions from spreading to the kidney

nephron

filtration units

• millions in kidney

1. renal corpuscle

2. renal tubule

cortical nephron

focuses on excretory and regulatory functions of the kidneys

• most numerous, 85% located in renal cortex

juxtamedullary nephron

plays a role in concentrating/diluting urine

• 15% of population located deep in the cortex

3 types of capillary beds

• glomerulus

• peritubular capillary bed

• vasa recta

helps to regulate filtration rate of urine and systemic blood pressure

3 steps in urine formation

1. Filtration by glomerulus

2. Reabsorption by peritubular capillaries

3. Secretion (reversed reabsorption) waste products are removed into urine

1. glomerular filtration

2. tubular reabsorption

3. tubular secretion

micturition

the act of emptying the bladder

• done by using the micturition reflex (spinal reflex)

composition of urine

derived from blood composition

• dependent on diet and cellular metabolism

5 characteristics of urine composition?

1. Color

2. Transparency

3. Odor

4. pH

5. Specific Gravity

What is urine comprised of?

95% water and nitrogenous wastes

What does a high pH indicate?

a vegetarian diet

Specific Gravity (SG)

weight of liquid relative to equal weight of distilled water

• water has SG of 1.000

• increased SG - concentrated urine

• decreased SG - diluted urine

casts

microscopic cylindrical structures produced by the kidneys in certain diseases

• microscopic crystals in urine

hydrometer

measures specific gravity of urine

gametes

sex cells that will be used to generate an offspring

• males = sperm

• females = egg or ova

meiosis

cell devision in sexually reproducing organisms that reduces the number of chromosomes in gametes

testes

main male reproductive organ

• located in scrotum

• generates sperm and hormones

• contains seminiferous tubules (where sperm is formed)

epididymis

surrounds testes and is the site for sperm maturation

semen

contains both seminal fluid (alkaline-protection for survival in vagina) and sperm

uterus

muscular organ which houses a fetus during development

follicle

contains ovaries

ovaries

the main organ in the female reproductive system

• generates eggs and hormones

• ejected via ovulation (once a month)

uterine/fallopian tube

where the egg travels from the ovary to the uterus

• fertilization occurs here

mammary gland

glandular organ located on the chest that produces milk

• purpose is to nourish an infant by producing milk and stimulated by estrogen

meiosis

gamete generation with sex cells being haploid (23 chromosomes)

gametogenesis

specific gamete generation

spermatogenesis

begins at puberty and continues throughout male life

• starts with stem cells called spermatogonia

• ends with round spermatid

spermiogenesis

generation of finalized sperm with tail

oogenesis

begins at fetal developments and stops at birth

• primary oocyte - arrested in prophase I

• starts with stem cells called oogonia

ends with ova

What does oogenesis produce?

1 egg and 3 polar bodies

How many chromosomes do sex cells contain?

23 - they need to be haploid

• each parent contributes 23

all other somatic cells are diploid (46 chromosomes)

crossing over

exchange of genetic material during sexual reproduction that results in recombinant chromosomes

recombination

enables genetic diversity

• two molecules of DNA exchange pieces of their genetic material with each other

round spermatid

mature form; end of spermatogenesis

finalized sperm

product of spermiogenesis that is functional and has tail

spermatogonia

stem cells at the beginning of spermatogenesis

oogonia

immature female reproductive cell; beginning of oogenesis

polar bodies

small haploid cell that is formed at the same time as an egg cell during oogenesis but does not have the ability to be fertilized

female menstrual cycle

(28-32 day process)

1. Menstrual - functional endometrium is shed off if fertilization doesn’t occur (day 1-5)

2. Proliferative - functional layer of endometrium is rebuilt by estrogen (day 6-14)

   1. ovulation occurs after day 14

3. Secretory - functional layer of endometrium receives enrichment of blood supplies and nutrients via glands (prepare for fertilization) (day 15-28)

endometriosis

painful condition where endometrial tissue grows outside of the uterus

• symptom is pelvic pain/cramping - associated with periods

prostate cancer

Prostate - small, walnut-shaped gland that produces seminal fluids

• most common cancer in men over 50 years old

• highest risk factor is genetics and age