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Terms in this set (220)

Is the second largest part or region of the brain.
o 10% of volume but 50% of neurons
• Develops from the metencephalon.
• Has a complex, highly convoluted surface covered by a layer of cerebellar cortex made of folds called folia.
• Composed of left and right cerebellar hemispheres.
• Separated from cerebrum by transverse fissure
• Each hemisphere consists of two lobes, the anterior lobe and the posterior lobe, which are separated by the primary fissure.
• Along the midline, a narrow band of cortex, the vermis, separates the left and right cerebellar hemispheres.
o The vermis receives sensory input the torso position and balance.
o Its' output to the vestibular nucleus helps maintain balance.
• The cerebellum is partitioned into three regions:
1. An outer gray matter layer of cortex.
2. An internal region of white matter, called the arbor vitae.
3. Cerebellar nuclei in the deepest layer.
Cerebellar Functions
• Coordinates and fine-tunes skeletal muscle movements and ensures that skeletal muscle contraction follows the correct pattern leading to smooth, coordinated movements.
• Coordinates repetitive body movements
• Coordinates complex learned, somatic motor patterns
o e.g., ride a bike, swing a bat
• Stores memories of previously learned movement patterns.
• Adjusts skeletal muscle activity to maintain equilibrium and posture.
• Receives proprioceptive (sensory) information from the muscles and joints and uses this information to regulate the body's position.
o Monitors the position of each body joint and its muscle tone.
A highly branched system of air-conducting passages that originate from the left and right primary bronchi.
• Progressively branch into narrower tubes as they diverge throughout the lungs before terminating in terminal bronchioles.
• Incomplete rings of hyaline cartilage support the walls of the primary bronchi to ensure that they remain open.
• Right primary bronchus is shorter, wider, and more vertically oriented than the left primary bronchus.
• Foreign particles are more likely to lodge in the right primary bronchus.
• The primary bronchi enter the hilum of each lung together with the pulmonary vessels, lymphatic vessels, and nerves.
• Each primary bronchus then branches into several secondary bronchi (or lobar bronchi).
o The left lung has two secondary bronchi since it has two lobes.
o The right lung has three lobes and three secondary bronchi.
• They further divide into tertiary bronchi.
• The right lung is supplied by 10 tertiary bronchi, and the left lung is supplied by 8 to 10 tertiary bronchi.
• Each tertiary bronchus is called a segmental bronchus because it supplies a part of the lung called a bronchopulmonary segment.
• As branching continues and the bronchioles become smaller, the following is observed:
o Incomplete rings of cartilage become smaller and less numerous
o All bronchi are lined with pseudostratified columnar epithelium
o Bronchi branch into bronchioles which lack rings of cartilage and are lined not with pseudostratified columnar epithelium but simple columnar or simple squamous epithelium
• Bronchi branch into smaller and smaller tubules that eventually reach the bronchioles, which are less than 1 mm in diameter
• Bronchiole walls are composed of a relatively thick layer of smooth muscle
Cecum
• First part of large intestine
• Blind sac located in lower right quadrant of abdomen
• Ileocecal valve represents junction between small intestine and large intestine
2. Ascending Colon
• Originates at the ileocecal valve and ascends right side of abdomen
• As it approaches the inferior border of the liver, it makes a 90-degree turn toward the left side of the abdominal cavity.
o This bend in the colon is called the right colic flexure, AKA hepatic flexure
3. Transverse Colon
• Originates at the right colic flexure and approaches the spleen in the upper left abdominal quadrant
• Suspended by the transverse mesocolon
• It makes a 90-degree turn inferiorly at the spleen.
o This bend in the colon is called the left colic flexure; AKA splenic flexure
4. Descending Colon
• Originates at the left colic flexure
• Found along the left side of the abdomen
• Makes contact with iliac fossa and terminates into the sigmoid colon
5. Sigmoid Colon
• Its shape resembles the letter S
• Turns inferomedially and is suspended by the sigmoid mesentery
• Terminates as the rectum
6. Rectum
• Muscular tube that readily expands to store accumulated fecal material prior to defecation
• Three thick transverse folds of the rectum called rectal valves ensure that fecal material is retained during the passage of gas
• The rectum terminates at the anal canal
7. Anal Canal
• Terminal few centimeters of the large intestine
• Passes through an opening in the levator ani muscles of the pelvic floor
• Anal columns line the internal surface of the anal canal
• Anal sinuses secrete mucin for lubrication during defecation
• Internal and external anal sphincters open and close the anal canal during defecation
Collectively produce and secrete saliva
o A fluid that assists in the initial activities of digestion
• Volume of saliva secreted daily ranges between 1.0 and 1.5 L
• Most is produced during mealtime, but smaller amounts are produced continuously to ensure that the oral cavity remains moist
• Water makes up 99% of the volume of saliva
• Also contains a mixture of other components
• Saliva serves the following functions:
• Moistens ingested materials to become a slick bolus
• Moistens, cleanses and lubricates the structures of the oral cavity
• Chemical digestion of ingested materials
o First step in chemical digestion occurs when amylase in saliva begins to break down carbohydrates.
• Antibacterial action
• Dissolves materials so that taste receptors on the tongue can be stimulated
• Three pair of salivary glands are located external to the oral cavity:
o Parotid gland
o Submandibular gland
o Sublingual gland
The Parotid Glands
• Largest salivary glands
• Each parotid gland is located anterior and inferior to the ear, partially overlying the masseter muscle.
• Produce about 25-30% of the saliva, which is conducted through the parotid duct to the oral cavity.
• Includes a parotid duct that runs parallel to the zygomatic arch and pierces the buccinator muscle just opposite the second upper molar
o Duct named Stenson's duct
• Also secretes amylase
The Submandibular Glands
• Inferior to the body of the mandible
• Produce most of the saliva (about 60-70%)
• A submandibular duct transports saliva & opens from each gland through a papilla in the floor of the mouth on the lateral sides of the lingual frenulum
o Duct named Wharton's duct
The Sublingual Glands
• Smallest sized salivary gland
• Inferior to the tongue and internal to the oral cavity mucosa
• Contribute only about 3-5% of the total saliva.
• Each gland extends multiple tiny sublingual ducts that open onto the inferior surface of the oral cavity, posterior to the submandibular duct papilla
o Duct named the Ducts of Rivinus
Salivary Gland Secretion
• Two types of secretory cells are found in salivary glands:
o Mucous cells: secrete mucin which forms mucus upon hydration
o Serous cells: secrete a watery fluid containing ions, lysozyme and salivary amylase
The teeth are collectively known as the dentition
o Responsible for mastication, the first part of the mechanical digestion process
• Have an exposed crown, a constricted neck and one or more roots that fit into dental alveoli
• Each root is enclosed within (covered) harden material called cementum
• Dentin forms the primary mass of the tooth.
o It is harder than bone and deep to cementum and enamel
• The external surface of the dentin is covered with a layer of enamel that forms the crown of the tooth
o Hardest substance in body!
• The center of the tooth is a pulp cavity that contains connective tissue called pulp
• A root canal opens into the connective tissue through an opening called the apical foramen.
o Blood vessels and nerves pass through this opening and are housed in the pulp
• Two sets of teeth develop and erupt in a normal lifetime:
o Deciduous teeth erupt between 6-30 months, are 20 in number, and are often called milk teeth
o Permanent teeth replace the deciduous teeth and are 32 in number
• The more anteriorly placed permanent teeth tend to appear first, followed by the posteriorly placed teeth.
Permanent Teeth
• Incisors: most anteriorly placed, shaped like chisels whose sharp edges bite off large pieces of food and have a single root
• Canines: posterolateral to the incisors, pointed tips for gasping, puncturing, and tearing food
• Premolars: posterolateral to canines, have flat crowns with prominent ridges called cusps for crushing and grinding
• Molars: thickest and most posterior teeth, also adapted for crushing and grinding of ingested materials
• The last teeth to erupt are the third molars, often called "wisdom teeth," in the late teens or early 20's.
• Often the jaw lacks space to accommodate these final molars, and they may either emerge only partially or grow at an angle and become impacted.
• Impacted teeth cannot erupt properly because of the angle of their growth.
• Retroperitoneal location
o The superior pole of the left kidney is at the level of T12, whereas the superior pole of the right kidney is about 2 cm lower to accommodate the large size of the liver
• Left Kidney is located 2cm higher than the right one.
o The superior pole of the left kidney is at the level of T12, whereas the superior pole of the right kidney is about 2 cm lower to accommodate the large size of the liver
• Hilum: a concave medial border where vessels, nerves, and the ureter connect with the kidney
o The hilum is continuous with an internal space called the renal sinus
• Tubing within the Renal Sinus:
o minor calyx
o major calyx
o renal pelvis - to the ureter
• Each kidney is surrounded and supported by several tissue layers (from deepest to most superficial):
o Fibrous capsule - dense irregular connective tissue in direct contact with outer surface of kidney
o Perinephric fat - provides cushioning and insulation to the kidney
o Renal fascia - anchors kidney to posterior abdominal wall
o Paranephric fat - outermost layer surrounding the kidney between renal fascia and peritoneum
Regions of the Kidney
• Divided into an outer renal cortex and an inner renal medulla
• Extensions of the renal cortex called renal columns project into the renal medulla and subdivide the medulla into renal pyramids (medullary pyramids)
• A typical kidney contains 8-15 renal pyramids
• The wide base of the renal pyramid makes contact with the cortex in a region called the corticomedullary junction
• The apex (tip) of the renal pyramid is called the renal papilla
• Each renal papilla projects into a hollow funnel-shaped structure called the minor calyx
• Several minor calyces fuse to form a major calyx
• The major calyces fuse to form the renal pelvis, which collects the total urine output from one kidney and transports it into the ureter
Beginning at the testis and extending through the penis, the ducts are:
o Rete testis
o Efferent ductules
o Epididymis
o Ductus deferens
o Ejaculatory duct
o Urethra
Rete Testis and Efferent Ductules
• The rete testis receive sperm from seminiferous tubules
• Efferent ductules connect the rete testis to the epididymis
Epididymis
• Situated on the posterosuperior surface of the testes, the epididymis consists of:
o Head
o Body
o Tail
Its head lies on the superior surface of the testis, while the body and tail are posterior to the testis.
• Internally, the epididymis contains a long convoluted duct of the epididymis
• The epididymis stores sperm and serves in the maturation process of sperm
o If they are expelled too soon, they lack the motility necessary to travel through the female reproductive tract and fertilize an oocyte.
o If sperm are not ejected from the male reproductive system in a timely manner, the old sperm degenerate in the epididymis.
Ductus Deferens
• Sperm leaving the epididymis enter the ductus deferens (vas deferens)
• This tube travels within the spermatic cord and enters the pelvic cavity through the inguinal canal
• As the ductus deferens approaches the prostate gland, it enlarges to form the ampulla
• The ampulla unites with the proximal portion of the seminal vesicle to form the ejaculatory duct

Ejaculatory Duct
• Formed by a uniting of the ductus deferens and the seminal vesicle
• Located within the substance of the prostate gland between 1-2 cm long and conducts sperm from the ductus deferens to the prostatic urethra
Urethra
• Transports semen from the ejaculatory duct to the outside of the body.
• Subdivided into:
o prostatic urethra that extends through the prostate gland
o membranous urethra that travels through the urogenital diaphragm
o spongy (aka penile) urethra that ends through the penis
• Sperm leave the body through the urethra.