week 11 Flashcards
Metabolism, pharmacology and reproductive system structure + function
What does nutrients do when absorbed
Used immediately for energy for active
processes
Synthesized into structural or functional
molecules
Converted to fat or glycogen for later use as
energy
2 types of metabolism
Anabolism & Catabolism
Catabolism
Breaking down
large molecule
into smaller units
Anabolism
Building more
complex molecules
from smaller ones
Metabolic Rate
• Total of all anabolic and catabolic processes underway • Basal metabolic rate (BMR) is the rate of energy used by a person at rest • Homeostatic regulation of body temperature
Factors that influence metabolic rate
• Surface area, age, gender, stress, and hormones • As the ratio of surface area to volume increases, BMR increases • Males have a disproportionately high BMR • Stress increases BMR • Thyroxine increases oxygen consumption, cellular respiration, and BMR
Carbohydrates
Catabolism:
Glycolysis
Anabolism:
Glycogenesis
Lipids
Catabolism:
Lipolysis
Anabolism:
Lipogenesis
Protiens
Catabolism:
Proteolysis
Anabolism:
Protein synthesis
Metabolism
• Extract components of biological
macromolecules from food and rebuild into
tissues
• Obtain energy stored in chemical bonds in
food and convert into a useful form
Cellular metabolism
• The end result of most chemical catabolism in the body is energy • This occurs in the cell • The three main molecules in the body that produce energy are carbohydrates, proteins and lipids in our diet • 40% of the energy released is captured in ATP and the rest is released as heat
ATP stand for
Adenosine triphosphate
Nutrient pool
• Large molecules are catabolised in the digestive system to become the smaller
molecules of glucose, amino acids, fatty acids and glycerol = “the nutrient pool”
• These smaller molecules can be absorbed through the intestinal wall into blood
and then to the liver
Carbohydrate metabolism
• Complex carbs are broken down in the GIT to glucose,
which is absorbed into the blood and sent to the liver
• The glucose is distributed throughout the body for
cellular metabolism, where it is used to produce energy
(ATP)
Cellular Respiration
Glucose is catabolized to produce energy in
three pathways:
1. Glycolysis
2. Krebs cycle (aka TCA or citric acid cycle)
3. The electron transport chain (ETC) and oxidative
phosphorylation
Glucose + Oxygen react to give water + carbon
dioxide + energy (ATP)
Lipid metabolism
- Energy rich fats and oils (esp triglycerides)
* Regulation similar to glucose metabolism
Protein metabolism
• Protein can be used as fuel if there is insufficient
carbohydrate or fat available
Absorptive and post-absorptive states
Metabolic controls equalise blood concentrations
of nutrients between two states
1. Absorptive
– The time during and shortly after nutrient intake
2. Post-absorptive
– The time when the GI tract is empty
– Energy sources are supplied by the breakdown of
body reserves
What is a drug
any substance that, when
taken or administered into the
body has a physiological effect
Oral drugs advantages and disadvantages
Advantages: • Convenient • Easy concordance • Cost-effective • No sterility restraints • Many forms available
Disadvantages: Poor bioavailability GIT irritation potential Dependant on • pH • Enzymes • Microbiome
Drug release
Immediate release
Delayed release
Extended release
Pharmacokinetics
Absorption
Drug gets into blood stream
- Route, bioavailability
Distribution
Drug gets around
- Protein binding, blood brain barrier, ?quarantined sites
Metabolism
Biotransformation
- First Pass Effect, Induction/Inhibition of metabolism
Excretion
Drug gets out of body
- Kidneys, bowel, lungs, skin
Male reproductive system
The male reproductive system makes male gametes
(sperm) & delivers them to the female reproductive tract
Female production system
The female reproductive system makes female gametes
(ova), delivers an ovum to the Fallopian tube, accepts the male gametes (sperm), and provides protective
environment for the developing foetus until birth
Breasts provide milk to nourish newborn baby
Sex gonads
Testes in males
Ovaries in females
- produce sex cells (gametes) and reproductive hormones
Scrotum function Male
- Sac of skin hanging outside the abdominopelvic cavity
- Houses testes and epididymides, keeps sperm at 3 °C lower than core body temperature to optimise sperm viability
Testes functions Male
- In scrotum — produces sperm and testosterone
Epididymis Male
- Also in scrotum alongside testes, comma-shaped
- Sperm mature/become motile & can be stored for months
Vas deferens function Male
duct from each epididymis through peritoneal cavity,
joins with duct of seminal vesicle -> delivers sperm to
urethra
Seminal vesicle function Male
posterior wall of bladder -> provides fluid for semen
Ejaculatory Duct function Male
- joins vas deferens to urethra
- passes through prostate gland
Prostate gland function Male
- inferior to bladder at proximal end of urethra -> provides the bulk of the fluid for semen
Bulbourethral gland function Male
inferior to prostate gland -> alkaline fluid lubricates & neutralises traces of acidic urine in urethra
Urethra function Male
Duct from bladder through prostate gland & penis -> transports both semen & urine (at different times…)
Penis function Male
- Ensures delivery of semen to
vagina
Contains erectile tissue - corpus spongiosum (surrounds urethra) and 2 corpora cavernosa run the length of the penis and fill with blood during sexual arousal (erection)
Sperm function male
- Are formed in seminiferous tubules
Testosterone function Male
- Is produced in interstitial (Leydig) cells, which lie between the tubules
Scrotum
- Houses testes and epididymides
* Nerves, blood vessels, and lymphatic vessels of testes pass in the spermatic cord
Meiosis
Cell division that takes places in the gonads to
produce sex cells (gametes)
• 2 consecutive cell divisions (Meiosis I and Meiosis II)
• Produces 4 daughter cells with a haploid number of
chromosomes (23)
Male reproduction
Sperm formation, which takes place in seminiferous
tubules of testes
• Begins at puberty & continues for life
• Approximately 400 million sperm are produced per
day
• 4 haploid sperm (23 chromosomes) produced from
each stem cell
• The whole process takes about 70–80 days
• Complete maturation of sperm takes place in the
epididymides
Sperm
Sperm consist of
• a head (containing DNA) with an acrosome “cap”
containing enzymes (to ensure penetration of the ovum)
• a “collar” of mitochondria
• a flagellum (tail)
Semen
- Mixture of sperm and fluid from the accessory glands
- Alkaline in nature to neutralise female acidity
- 2–5 ml per ejaculation
- 50–150 million sperm/ml of semen
- = 100–750 million sperm/ejaculate
Ovaries function female
• Make ova, oestrogens, and progesterone
• Located on each side of uterus — held by ligaments
• Peritoneal fold “tents” over uterus and supports uterus,
uterine tubes, vagina
• Accessory structures • Uterus, Fallopian (uterine) tubes, vagina
Uterus function female
Receives and nourishes fertilised ovum
• Consists of body, fundus, cervix
Fallopian tubes function female
Extends laterally from each side of uterus, open to peritoneal cavity, terminates in fimbriae near each ovary
• Site of fertilisation
Vagina function female
Receives penis and is an outlet for menstrual fluid and baby.
External genitalia
Labia majora, labia minora, clitoris
Perineum
Skin and underlying muscles between vulva and anus
Breasts
• Mammary glands produce & secrete milk
Uterus
- A pear-shaped organ with 3 layers
- Peri, Myo, and Endometrium
- Endometrium thickens each menstrual cycle and functional layer sloughs off (menstruation), if fertilisation does not occur
Ovaries
• Each ovary has outer cortex containing ovarian follicles.
• Each follicle consists of an oocyte (immature ovum) surrounded by
cells. If one layer -> follicle cells; if more than one layer ->
granulosa cells.
• Inner region of the ovary is medulla -> contains nerves, and blood/lymphatic vessels
Oogenesis
• Begins in female foetus
• At birth a female’s lifetime supply of primary oocytes
(up to a million) are in place in immature ovarian
cortex
• At puberty, a small number of these are activated each
month
• Usually only one will become a functional gamete
(ovum) per menstrual cycle
Corpus luteum (Yellow body)
The “empty” vesicular follicle
• A hormone factory -> produces oestrogen and progesterone
Corpus albicans (White body)
• Remnants of the corpus luteum after it degenerates at the end of menstrual cycle
ANS sexual activity
Parasympathetic reflexes are involved in arousal
Sympathetic activity contributes to ejaculation & orgasm
(e.g., HR and BP increase)
