L1c - Tissues & Systems (3) Flashcards
What are the functions of the renal system?
- Filtration of blood and removal of waste products (urine production)
- Calcitriol formation
- Erythropoietin production and release
- Ion level regulation & acid base balance
- Blood pressure regulation
- Gluconeogenesis
What are the primary anatomical structures of the renal system?
- Kidneys (2)
- Ureters (2)
- Urinary Bladder (1)
- Urethra (1)
Describe the shape of the kidney.
- Symmetrical
- Bean shaped
What is the approximate size and weight of the kidney?
- Same size as hand to second knuckle
- 100g
What is the hilum?
Point of connection for blood vessels, ureters and nerves.
Where are adrenal glands found?
On the superior pole
Describe the location of the kidneys.
- Found in the retroperitoneal space
- Posterior to the parietal peritoneum
- About the level of T12 to L3
What is unique about the location of the right kidney?
Right kidney is slightly lower due to size and position of liver
Describe the key anatomical features of the kidney.
- Outer renal cortex
- Inner renal medulla
Describe the flow of urine in the renal system.
Collecting ducts -> Minor calyx -> Major calyx -> Renal pelvis -> Ureter
What is the corticomedullary junction?
The boundary between the cortex and medulla
What is the purpose of the renal columns?
Separate structures of the renal medulla into renal pyramids
Describe calcitriol formation with reference to kidneys.
- Kidneys synthesise final enzyme pathway for calcitriol formation
- Calcitriol increases absorption of calcium from small intestine to increase blood Ca2+ concentration
Describe erythropoietin production and release with reference to kidneys.
- As blood passes through the kidneys, the kidney cells detect oxygen levels
- If low, EPO hormone is secreted
Describe ion level regulation & acid-base balance with reference to kidneys.
- Secretion and resorption of ions through walls of nephrons (kidney cells) help control inorganic ion balance (Na+, K+, Ca2+, PO43-)
- Same for acid-base (altering levels of H+, HCO3-)
Describe gluconeogenesis with reference to kidneys.
During periods of extreme fasting / starvation, kidneys may help to maintain blood sugar levels by producing glucose from non-carbohydrate sources
What is a nephron?
Functional filtration unit
What are the 2 main structures of kidneys?
- Renal Corpuscle (glomerulus and glomerular capsule)
- Renal Tubule (proximal convoluted tubule, nephron loop, distal convoluted tubule)
How is blood filtered in the kidneys?
- Blood is filtered through glomerular walls into capsule and drains into the renal tubule
- Specialised absorption and secretion mechanisms occur at specific points along the tubule to ensure that balance is maintained and essential products are not lost to the urine
Describe the 2 types of nephrons.
- Cortical (80-85%)
- Juxtamedullary (15-20%):
Longer loops, allow formation of a salt concentration gradient in interstitial space outside the nephron loop, collecting tubules and collecting ducts; responsible for concentrating urine (regulated by ADH)
How is urine formed?
- Filtration
- Tubular reabsorption
- Secretion
What happens when loop diuretics alter the slat gradient?
Less fluid is pulled back into the interstitial fluid, and more remains in the urine
Describe what happens to glucose in the renal system.
- Freely filtered
- Usually completely reabsorbed by the proximal convoluted tubule (specific transporters)
- Certain maximum that can be reabsorbed per unit time, so if levels in the filtrate exceed capacity for reabsorption, glucose will be detected in the urine
What do diuretic drugs do?
- Increase excretion of urine
- Mobilise fluids
- A common treatment for hypertension
Describe the role of thiazide diuretics.
- Work in the distal convoluted tubule and alter Na+ reabsorption
- If less Na+ is reabsorbed, less water is reabsorbed, so more remains in the urine
- Allow filtration but not reabsorption
What do ureters do?
Conduct urine from hilum of kidneys to the posterolateral wall of the urinary bladder.
What is the urinary bladder?
An expandable, muscular reservoir for urine
Where is the urinary bladder positioned?
- Immediately posterior to the pubic symphysis
- Anterior to the uterus in females
- Directly above the prostate in males
How does the shape of the urinary bladder change?
- Pyramidal when empty
- Distends superiorly when filling until oval shape
What is the urinary bladder lined with and what effect does this have?
- Lined with transitional epithelium
- Accommodates the stretch and change in shape with filling
- Cuboidal to squamous
- Greater distension allowed due to mucosal folds
Describe the action of smooth muscle bundles in the urinary bladder.
- Smooth muscle bundles form the detrusor muscle
- Contracts when bladder empties
Describe the role of urethral sphincters in the control of urine flow and micturition.
Internal Urethral Sphincter
- Involuntary control
- Autonomic nervous system
External Urethral Sphincter
- Voluntary control
- Somatic nervous system
What are gonads?
Primary reproductive organs (ovaries and testes)
What are gametes?
Sex cells (unite at fertilisation)
What is the role of sex hormones?
Affect maturation, development and changes in reproductive system activity
What are accessory reproductive organs?
Include ducts for transport of gametes
What is the perineum?
- Urogenital Triangle
- Anal Triangle
(diamond-shaped area between the thighs in males and females)
Describe the location of the perineum.
Bounded:
- Anteriorly by the pubic symphysis
- Laterally by the ischial tuberosities
- Posteriorly by the coccyx
The perineum can be divided by an imaginary horizontal line into what?
- Anterior urogenital triangle
- Posterior anal triangle
Describe the urogenital triangle.
- Contains urethral and vaginal orifices in females
- Contains base of penis and scrotum in males
What is the anal triangle?
- Location of anus
- Surrounded by the external anal sphincter
What are the primary reproductive organs of the female reproductive system?
Ovaries
What are the accessory reproductive organs of the female reproductive system?
- Uterine tubes
- Uterus
- Vagina
- Clitoris
- Mammary glands
The peritoneal folds, finding ‘pouches’ as it lies over the top of the pelvic cavity structures. Name these pouches.
- Vesicouterine (bladder and uterus)
- Rectouterine (rectum and uterus)
Describe the mammary glands of the reproductive system.
- Located on anterior thoracic wall
- Composed of a tubuloalveolar exocrine gland
- Produces milk = nutrition for infants
- Subdivided into lobes, and then further subdivided into lobules
Describe the suspensory ligaments of the reproductive system.
- Fibrous connective tissue bands
- Provide internal support
- Attach to the deep fascia overlying the pectoralis muscles
Describe the action of mammary glands in females.
- Tiny ducts from the alveoli drain milk
- These merge to form lactiferous ducts
- Ducts enlarge to form a lactiferous sinus close to the nipple where milk is stored prior to release
Describe the role of the hormone prolactin.
- Produced in anterior pituitary
- Responsible for milk production
- Begins shortly after giving birth
Describe the process of lactation.
- Lactation is the process of release of milk
- Triggered by increased oxytocin levels
- Produced in the hypothalamus
- Released from the posterior pituitary
What are the primary reproductive organs of the male reproductive system?
Testes
What are the accessory reproductive organs of the male reproductive system?
- Complex system of ducts and tubules
- Penis
Describe the epididymis of the male reproductive system.
- Stores sperm until fully mature
- Unexpelled sperm are reabsorbed
Describe the ductus deferens of the male reproductive system.
- Travels within spermatic cord and through inguinal canal, dropping back over the bladder
- Enlarges to form ampulla as it meets seminal vesicle (behind bladder, above prostate)
- Carries motile sperm
Describe the ejaculatory duct of the male reproductive system.
- Formed by union of ampulla of ductus deferens and seminal vesicle
- Carries sperm from testes and component of seminal fluid from seminal vesicle into prostatic urethra
Describe the urethra of the male reproductive system.
- Passes from bladder (internal urethral sphincter) through prostate (prostatic urethra)
- Seminal fluid merges with prostatic fluid (various components to ensure sperm health, nutrition and motility)
- Membranous urethra passes through urogenital diaphragm
- Spongy urethra passes through penis
Describe the seminal vesicles of the male reproductive system.
- Produce alkaline fluid to aid in sperm health
- Produces fructose for nutrition of sperm
Describe the prostate gland of the male reproductive system.
- Produce PSA and citric acid (health and nutrition)
Why is PSA useful?
Useful marker for prostate health
Describe the bulbourethral glands of the male reproductive system.
Produce protective mucous
What are the functions of the digestive (gastrointestinal) system?
- Ingestion (introduction of solid and liquid nutrients)
- Motility (voluntary and involuntary movement)
- Secretion (facilitation of digestion: enzymes, acid and bile)
- Digestion (mechanical: chewing and mixing, chemical: enzymatic degradation/changes)
- Absorption (passive and active transport into blood or lymph)
- Elimination (expulsion of indigestible components)
What are the 2 main categories of the organs of the digestive system?
- Those that make up the gastrointestinal (GI) tract
- Accessory organs
Describe the GI tract.
- Continuous tube (upper and lower)
Includes:
- Oral cavity
- Pharynx
- Oesophagus
- Stomach
- Small intestine
- Large intestine
- Rectum
- Anus
Name the accessory digestive glands.
- Salivary glands
- Liver
- Pancreas
Name the accessory digestive organs (NOT GLANDS).
- Teeth
- Tongue
- Gall bladder
What is the stomach?
A muscular sac responsible for mechanical and chemical digestion
Describe the passage of bolus.
Bolus passes down oesophagus and into stomach
What main parts does the stomach comprise of?
- Cardia
- Fundus
- Body
- Pylorus
What is the purpose of the gastric folds in the stomach?
Allow expansion and flexibility
What are many abdominal organs held in place by?
Double-layered serous membranes known as mesenteries
What is the greater omentum?
‘Apron’ that extends from the greater curvature of the stomach and covers most abdominal organs.
What is the lesser omentum?
Connects lesser curvature of the stomach and the duodenum to the liver
What is the falciform ligament?
Attaches liver to anterior abdominal wall
What is the mesentery proper?
Fan-shaped peritoneal fold that suspends most of small intestine from internal surface of posterior abdominal wall
What is the mesocolon?
Fold in peritoneum that suspends parts of large intestine to internal surface of posterior abdominal wall.
(Name denotes attachment: i.e. transverse mesocolon, sigmoid mesocolon)
Describe the liver and its function.
- Largest internal organ
- Main digestive function = production of bile
- Left and right love (including quadrate, and caudate lobes)
Describe the passage through the gall bladder.
1) Left and right hepatic ducts merge to form a common hepatic duct.
2) Common hepatic and cystic ducts merge to form a common bile duct.
3) Main pancreatic duct merges with common bile duct at the hepatopancreatic ampulla, which extends into the duodenum.
4) Bile and pancreatic juice enter duodenum at the major duodenal papilla.
Describe the 2 main functions of the pancreas.
- Endocrine Function (insulin, glucagon)
- Exocrine Function (acinar cells -> pancreatic juice; digestive enzymes)
