A&PII Unit 4 Examination Concepts

Two groups of digestive system

Alimentary canal (GI tract): mouth, pharynx, esophagus, stomach, small intestine, and large intestine)

Accessory organs: teeth, salivary glands, pancreas, liver and gallbladder

What portion of the alimentary canal is considered the gut

Stomach, small intestine, large intestine

Anatomy of the Mouth

Site where food enters and is held between the teeth and tongue by lips and cheeks

• Hard palate and soft palate form the roof anteriorly and posteriorly

• Lingual frenulum holds the tongue to the floor of the mouth

• Palatine tonsils and the lingual tonsils protect the entrance to the pharynx

Anatomy of Pharynx

Divided into oropharanyx (posterior oral cavity) and larynopharynx (continuous with esophagus)

Anatomy of the esophagus

Connects pharynx and stomach

Has four tissues:

• Muscosa - innermost later lining the lumen of the GI tract

• Submuscosa - deep to mucosa; made of connective tissue containing blood vessels, nerves, MALT, and lymphatic vessels

• Muscularis externa - smooth muscle layer with inner circular layer and outer longitudinal later

• Serosa - outermost layer

Anatomy of Stomach

Located on the left side of the abdominal cavity

Food enters via cardioesophageal sphincter and exits via pyloric valve

Anchored to liver at lesser curvature via lesser momentum and is covered anteriorly by the greater omentum

Anatomy of small intestine

Three sections

• Duodenum

• Jejunum

• Iluem

Joins the large intestines at the ileocecal valve

Protected by Peyer’s patches

Anatomy of large intestine

Extends from the ileocecal valve to the anus

Subdivisions

• Cecum - first part

• Appendix - hangs off cecum

• Colon -

  • Ascending colon

  • Transverse colon

  • Descending colon

• Rectum

• Anal Cana

  • External anal sphincter (voluntary)

  • Internal anal sphincter (involuntary)

The two sets of teeth

Help masticate food

• Deciduous teeth (baby/milk)

• Permanent teeth

  • full set is 32 teeth with wisdom teeth

Shape and functions of teeth

• Incisor - cut

• Canines - tear or pierce

  • Premolar and molars - grind and crush

Anatomy of teeth

• Crown - exposed part of tooth covered by enamel

  • Dentin is under enamel

  • Pulp cavity is under dentin and contains pulp

• Root canal carries blood vessels and nerves to pulp cavity

• Gingiva - gum

• Root - part of tooth embedded in the mandible

• Neck - connect crown and root

Salivary glands

Three pairs empty into the mouth

• Parotid glands

• Submandibular glands

• Sublingual glands

Pancreas

Retroperitoneal organ extending from spleen across abdomen to the duodenum

Produces enzymes that digest all classes of nutrients

Liver

Largest gland in body and has four lobes

Produces bile

Galbladder

Stores bile when it backs up the cystic duct upon being denied entry to the duodenum

Functions of digestive systems

Breakdown foods and absorb nutrients

Waste product defacation

Six main processes of digestive system

1. ingestion - taking in food

2. Propulsion - movement of foods through the GI tract

3. Mechanical breakdown - physical grinding of foods into smaller pieces as they mixed with digestive juices

4. Digestion - involves enzymes that chemically breakdown food

5. Absorption - transporting of digested products into the blood or lymph

6. Defecation - elimination of waste as feces

Activities occurring in the mouth, pharynx, and esophagus

Food mechanically broken down as it is chewed while the tongue mixes it with saliva

Pharynx and esophagus have no digestive function (routes to move food)

Deglutition (swallowing)

• Buccal phase: occurs in the mouth when the tongue forces the food bolus toward the pharynx

• Pharyngeal-esophageal phase: transports food through the pharynx and esophagus

Activities of the stomach

Neural and hormonal signals control gastric juice secretion

• Gastrin - release is stimulated by food and rising pH; stimulates pepsinogen, mucus, and HCl production

• Pepsinogen is activated to pepsin

• As stomach walls stretch to accommodate food, muscle layers begin contracting

Activities of the small intestine

Chyme continues chemical digestion in the small intestine through action of the brush border enzymes and pancreatic juice

Hormones released:

• Secretin - stimulates liver to produce more bile and pancreas to release bicarbonate-rich pancreatic juice

• CCK - signals the gallbladder to contract, released bile from storage and stimulates pancreas to release enzyme-rich pancreatic juice

• Absorption occurs by a mixture of diffusion and active transport

• Materials remaining in small intestines enters large intestines (water, fiber, and many bacteria)

A

Activities of large intestine

• Colon produces no digestive enzymes and absorbs mainly water, ions, and vitamins

• Resident bacteria metabolize some remaining foodstuff and release gases

• Haustral contractions - cost common; slow segmenting

• Mass movements - long, slow, powerful wavelike contractions that move over large areas of the colon several times per day

• When contents reach stretch the walls of the rectum, the defecation reflex is initiated

Microbiota

Includes all microbes (bacteria, fungi, viruses, parasites) that live on or inside the human body

outnumber human cells 10 to 1

health and diversity influence immunity, how our bodies use energy, food cravings, mood, allergy, and autoimmune disease

Major nutrients

Proteins: eggs, meats, fish, meat products, and combinations of grains and veggies that provide all eight essential amino acids

Carbohydrates (sugars and starches): come from plants

Lipids (fats, usually consume triglycerides): saturated come from animal products and unsaturated come from plants

Minor nutrients

Vitamins: organic nutrients in foods, act as coenzymes

Minerals: inorganic nutrients required by the body

Metabolism

Includes all chemical reactions in the body

• Catabolism - breakdown of substances into smaller, simpler ones

  • Broken bonds are used to make ATP

• Anabolism - buildup of substances into larger, more complex ones

Carbohydrate metabolism

Major source of ATP

Reactions that use oxygen to ultimately generate ATP are referred to as cellular respiration

• Glycolysis: glucose → pyruvate (two molecules per one glucose); small amount of ATP produced

• CAC: processes pyruvate, transferring hydrogens and their electrons to electron carriers, while will proceed to ETC

• ETC: transfers the electrons carried from CAC down a gradient of carrier proteins to harness energy to make many ATPl hydrogen ions and electrons unite with oxygen to form water

Fat metabolism

Most concentration form of stored energy

Used to make or repair cell membranes, myelin sheaths, and fatty cushions around some organs

When glucose is lacking, fats are used for ATP synthesis

By-products can build uo in blood and lower pH (acidosis/ketoacidosis)

Protein metabolism

used to make both functional and structural proteins

used to make ATP only when in excess or when sugars and fats are not available, such as during starvation

Function of urinary system

Filters nitrogenous waste

Electrolyte regulation and transportation

Also help regulate blood pressure by producing the enzyme renin

Organs of the Urinary System

Kidney

Ureter

Bladder

Urethra

Location and Structure of Kidneys

Located along the dorsal wall in a retroperitoneal position from vertebra T12-L3

Each roughly the size of a large bar of soap

Sit inferior to the adrenal glands and

Three protective layers:

• renal fascia (most superficial)

• perirenal fat capsule

• fibrous capsule

Distinct regions

• Renal cortex: outer light region

• Renal medulla: inner darker region with pyramids

  • Renal columns: separated by renal columns

• Hilum - indentations and grooves

How is blood supplied to the kidneys

Renal artery

Segmental arteries

Interlobar arteries

Arcuate arteries

Cortical radiate arteries

How is blood drained from the kidneys

Cortical radiate veins, arcuate veins, interlobar veins, renal veins

Nephron

Functional cells of kidneys

• Filtration

• Reabsorption

• Kickstart secretion

Each kidney has over a million

Two parts: renal corpuscle and glomerular capsule

Each is associated with two capillary beds

• Glomerulus

• Peritubular capillaries

Steps of filtrations

1. Glomular filtration - water and solutes smaller than proteins are forced through the capillary walls and pores of the glomerular capsule into the renal tubule (passive process)

2. Tubular reabsorption - water, glucose, amino acids, and needed ions (only viable products) are transported out of the filtrate into the tubule cells and then enter the capillary blood

3. Tubular secretion - H+, K+, creatinine, and drugs are removed from the peritubular blood and secreted by the tubule cells into the filtrate

Nitrogenous waste products

generally not reabsorbed because the body does not need them

Urea, uric acid, creatine

Urine

Fluid remaining after tubular reabsorption and tubular secretion

Clear, yellow, sterile, and slightly aromatic

pH can vary but about 6

specific gravity is 1.035

Ureters

Carry urine from renal pelvis to the bladder (propelled by peristalsis, not gravity)

Bivalular

8 cm

Urinary Bladder

Smooth, collapsible, muscular sac that stores urine temporarily

500 mL

Trigone is a triangular area that includes the openings from both ureters and the urethral opening

Lined with transitional epithelium (stretches to accommodate more urine volume without increasing internal pressure)

Urethra

Passageway that carries urine from bladder outside the body

Two sphincters

• Internal urethral sphincter (involuntary)

• External urethral sphincter (voluntary)

ADH

Antidiuretic hormone

water retention

Aldosterone

Acts on kidney tubule to stimulate sodium ion reabsorption and potassium ion secretion

Chloride ions are reabsorbed with sodium ions

Functions of the reproductive system

Produce gametes

Survival of species and produce offspring

• Men produce sperm through testes

• Women produce ova through ovaries

The Testes

Attached to the trunk via the spermatic cord, a bundle enclosing nerves, blood vessels, and the ductus deferens

Divided into lobules that contain several seminiferous tubules, where sperm is produced

• between them are interstitial cells that produce testosterone

D

Duct System for the Male Reproductive System

Transports sperm from the body

Includes epididymis, ductus deferens, and urethra

After sperm is produced, enter epididymis, where they mature from 20 days

External genitalia for Males

Scrotum - houses testes outside the body

Penis

• Shaft

• Glans penis (enlarged tip)

• Prepuce (foreskin)

• Erectile tissues

Male reproductive functions

Spermatogenesis - sperm production

• begins with stem cells that divide

• Each forming a stem cells and a primary spermatocyte, which undergoes meiosis to form spermatid

Spermiogenesis - process by which a spermatid develops into a fully formed sperm

Testosterone

Essential for spermatogenesis and is produced by interstitial cells when signaled by LH

Also responsible for development of secondary sex characteristics

Ovaries

Primary reproductive organs

Contain ovarian follicles that each contain a developing oocyte surrounded by follicle cells

Vesicular follicle is mature

Duct system for female reproductive system

• Uterine (fallopian) tube - where ova develops

• Uterus - receives, retains, and nutures the fertilized eggs

  • Walls include: perimetric, myometrium, and endometrium

• Vagina - female copulatory organ and the birth canal

External genetalia for females

Vulva

• Mons pubis

• Labia majora

• Labia minora

• Vestibule

• Clitorus

• Greater vestibular glands

• Perineum

Female Reproductive Functions

Females are born with total supply of ova will have

• Oogenesis - production of eggs

  • begins with stem cells (oogonia) that produce primary oocytes

• At puberty, ovarian cycle begins

• A surge of LH triggers ovulation

  • meiosis II is completed to form an ovum only if the secondary oocyte is fertilized

Hormone production by the ovaries

Begin producing hormones at puberty

Estrogen is main female sex hormone

• Drives ovarian cycle and stimulates the secondary sex characteristics (breast development), growth of axillary and pubic hair, increased fat deposits, widening and lightening of pelvis

Progesterone - produced by corpus lute in response to presence of LH

Menstrual Cycle

28 days

• Menstrual phase (days 0-4) - when the endometrium lining is shed

• Proliferative phase (days 5-14) - when endometrium begins to regenerate, glands form in it, and blood supply increases

• Secretory phase (days 15-28) - when increasing progesterone levels stimulate more endometrial gland secretions and further development of blood supply

If no fertilization occurs, progesterone levels decline, endometrial lining is shed as blood vessels kink in response to low ovarian hormone levels

Pregnancy

Embryo - fertilization through week 8

Fetus - week 9 through birth

Childbirth

Dilation - the time from the beginning of true contractions until the cervix is fully dilated

Expulsion - the time from full dilation to delivery of the infant

Plancental - delivery of the placenta and membranes (afterbirth)