Concepts in Science Biological Sciences Final

What is the order in which food is processed in the alimentary canal?

• Oral Cavity

• Pharynx

• Esophagus

• Stomach

• Small intestine

• Large intestine

• Rectum

• Anus

What are the four steps of food processing?

• Ingestion

• Digestion

• Absorption

• Elimination

What are the two parts of digestion?

• Mechanical Digestion

  • E.g. Breaking down food with teeth

• Chemical Digestion

  • E.g. Enzymatic hydrolysis

What are the main functions of accessory organs in the digestive system? What are these organs?

• Produce secretions that aid chemical digestion

  • The latter 3 are found in the vicinity of the duodenum

    • Salivary glands

    • Liver

    • Gallbladder

    • Pancreas

What are the 3 salivary glands?

• Parotid

• Submandibular

• Sublingual

What are the main functions of the mouth?

• Moistens foods with saliva from salivary glands

  • Becomes bolus

• Grinds food with teeth and tongue (mechanical digestion)

• Begins chemical breakdown of starch

What is an Epiglottis?

• A door-like structure made of cartilage which allows you

  • To breathe by opening the entrance to the trachea and closing the esophagus.

  • To swallow food by closing the entrance to the trachea and opening the esophagus.

What is an Esophagus?

• Muscular tube that carries food to the stomach

• Peristalsis

  • Smooth muscles contract and relax, forming a ‘wave’

What is the stomach?

• Stores materials

• Produces digestive enzymes and HCl (gastric juice)

• pH of HCI is low (2)

• Protein digestion begins here

  • Produces pepsin (enzyme)

Describe the interior surface of the stomach wall.

• Highly folded and dotted (with epithelial tissue) with pits leading into tubular gastric glands.

  • The gastric glands have three types of cells that secrete different parts of the gastric juice:

    • Mucus, Chief, Parietal

What type of cells secrete mucus? What is mucus?

• Mucus cells

  • Lubricates and protects the cells lining the stomach

What type of cells secrete pepsinogen? What is Pepsinogen?

• Chief cells

  • Pepsinogens are an inactive form of the enzyme pepsin.

What type of cells secrete HCI?

Parietal cells

How does Pepsinogen and HCI interact?

• Pepsinogen and HCI are secreted into the stomach

• HCI converts pepsinogen to pepsin

• Pepsin then activates more pepsinogen into pepsin

  • Starts a chain reaction

• Proteins → (Pepsin breakdown) → smaller protein chains

What are the sphincters that are before and after your stomach called? What is their purpose?

• Cardiac and Pyloric, respectively.

• Regulates the entry of food into the small intestine

What is the small intestine?

• The majority of chemical digestion occurs here

• Absorption of nutrients into the blood

  • Nutrients diffuse into the bloodstream and are delivered to the rest of the body (where there’s a low concentration gradient)

• Secretion of digestive enzymes

• Surface area increased by villi

  • Villi are supplied with a rich supply of blood capillaries

What are the 3 areas in the small intestine?

Duodenum, Jujenum, Ilium.

What enzyme is secreted to digest Maltose? And what does it digest into?

Pancreatic Amylase and it digests into Glucose.

What is the process of breaking down starch (carbs)?

• In the mouth, starch → ( salivary amylase) → maltose

• In the small intestine, maltose → (pancreatic amylase) → glucose

what is the process of breaking down proteins?

• In the stomach, polypeptides → (pepsin) → short chains of amino acids

• In the small intestine, short chains of amino acids → (pancreatic trypsin) single amino acids

What is the process of breaking down lipids (fats)?

• Both occur in the small intestine

  • Large fat droplets → (bile) → smaller fat droplets

    • This process is called emulsification

  • Smaller fat droplets → (pancreatic lipase) → glycerol + 3 fatty acids

What are the main function of the 3m large intestine (Colon)?

• Reabsorption of water into the bloodstream

• Storage and elimination of solid wastes

• Secretion of mucus to allow passage of solids

• Decomposition of organic materials with the help of bacteria

• Production of vitamins (eg, K)

How is the large intestine arranged?

• Up (ascending)

• Across (transverse)

• Down (descending)

What is the Pancreas?

• Production of digestive enzymes

  • Amylase, Lipase, Trypsin

• Enzymes are exported from the pancreas via the pancreatic duct into the small intestine

• Production of hormones

  • Insulin and Glucagon

What are the main functions of the liver?

• Production of bile salts

• Detoxification (e.g. alcohol)

  • Digestive system → Circulatory system

    • Hepatic portal vein

• Storage of glucose in the form of glycogen

What are the main functions of the gallbladder?

• Store and concentrate bile

• Bile from gallbladder released into the small intestine

What type of circulatory system do humans have?

• Double circulatory system

  • Pulmonary circuit and systemic circuit

  • Blood goes through the heart twice

How many chambers does the human heart consist of?

• 4 chambers

  • 2 Atrium at the top

  • 2 Ventricles at the bottom

How many valves are in the heart?

• Four valves (which prevent the backflow of blood)

• Always from top to bottom, Atrium to Ventricle

  • Right atrium to right ventricle

  • Left atrium to left ventricle

  • Ventricle to pulmonary artery

  • Ventricle to aorta

What are the differences between arteries and veins?

• Arteries carry blood away from the heart

• Veins carry blood to the heart.

Left side of the heart pumps only ___?

Oxygenated blood

Right side of the heart pumps only ___?

Deoxygenated blood

What is the Pulmonary circuit and Systemic circuit?

• Pulmonary carries blood between the heart and lungs

• Systemic carries blood between the heart and the rest of the body

What is the valve called between the right atrium and the right ventricle?

Tricuspid valve

What is the valve called between the left atrium and left ventricle?

Bicuspid valve

What is the Superior and Inferior vena cava

• Bring in deoxygenated blood from the body

  • Superior vena cava - Top of Right Atrium

  • Inferior vena cava - Bottom of Right Atrium

What is Aorta?

• Delivers blood to rest of body tissues via arteries

• Arteries branch off from aorta

  • Named for the organs they deliver blood to

Describe the process of blood going through the heart

• Deoxygenated Blood

  • O2-poor blood from body → Right Atrium → Tricuspid Valve → Right Ventricle → Pulmonary Trunk → (L/R) Pulmonary Arteries → Lungs

• Oxygenated Blood

  • O2-rich blood from the lungs → (L/R) Pulmonary Veins → Left Atrium → Bicuspid valve → Left Ventricle → Aorta → To rest of body

What are capillary beds?

• Small blood vessels that are involved in gas exchange

• Branches of both arteries and veins

What is blood?

• A type of connective tissue

• 4-6 litres in human body

• Consists of cells and liquid called plasma

• 3 Types of cells in blood

  • Red Blood Cells (Erythrocytes)

    • Transport of Oxygen / Nutrients

  • White Blood Cells (Leukocytes)

    • Involved in Immunity

  • Platelets

    • Responsible for Blood Clotting [through fibres called Fibrin]

What is plasma?

• The liquid portion (55%) of blood, which contains:

  • Water

  • Electrolytes

  • Plasma proteins

What is hemoglobin?

• Proteins in red blood cells that carry oxygen.

  • Rich in iron due to heme group

  • Hemoglobin must reversibly bind O2, loading O2 in the lungs and unloading it in other parts of the body

  • Abnormally low amount of hemoglobin or low number of red blood cells causes anemia

What is the growth of plaque on the inner wall of the arteries called?

Atherosclerosis (Blood clot is more likely to become trapped)

What causes heart attacks?

Blockage of the coronary arteries

What is a coronary artery?

blood vessel that supplies the heart with oxygen

What is a stroke?

• The death of nervous tissue in the brain, usually resulting from rupture or blockage of arteries in the head

  • Caused by smoking, lack of exercise, poor diet, high blood pressure, high cholesterol level, genetic predisposition

What are varicose veins?

Twisted veins, caused by mechanical stress, aging, genetic predispositions

What is the anatomical pathway of air?

• Nostril → Nasal Cavity → Pharynx → Larynx → Trachea → Primary/Secondary/Tertiary/Smaller Bronchi → Bronchioles → Alveoli (Lungs)

What is diffusion in the respiratory system?

• Gas exchange across respiratory surfaces (alveoli to pulmonary capillaries) takes place by diffusion

  • Diffusion of Oxygen and nutrients out of capillary and into tissue cells

  • Diffusion of Carbon Dioxide and wastes out of tissue cells and into capillary

What happens when we inhale? When we exhale?

• Inhaling air

  • Rib cage expands as rib muscles conract

  • Diaphraghm contracts (moves down)

  • Volume of the chest cavity increases, which results in the low pressure in the chest cavity compared to the outside air pressue

    • As a result, air flows in

• Exhaling air

  • Diaphragm and chest wall return to normal, relaxed position

  • Muscular contraction is not involved. Muscles are relaxed.

What is the upper respiratory tract?

• Consists of Nose, Pharynx and Larynx

• Function to: warm, moisten, and filter incoming air

• Nose:

  • Lined with ciliated epithelium

  • Covered in mucus and washed by tears

  • Has significant blood supply (to warm incoming air)

What is the Larynx?

• Made of cartilages

• Thyroid cartilage (largest) at the front

• Adam’s apple in men (result of testosterone production)

• Called “voice box” because of the location of vocal folds (cords)

What are some diseases related to respiratory health?

• Sinusitis

  • Inflammation (swelling) of the membranes lining sinuses

• Bronchitis

  • Inflammation of bronchi

• Asthma

  • Inflammation of bronchi, increased production fluids; allergic reactions

• Pneumonia

  • Inflammation of alveoli, fluid in alveolar sacs. Caused mainly by bacteria

• Lung Cancer

  • Smoking damages the tissue of the lungs

What is asexual reproduction known as?

• Budding - Common in invertebrates, an organism produces offspring by producing individual outgrowths from existing ones.

• Fission - a parent organism divides/separates to create two or more offspring of the same size

• Fragmentation - Common in plants, breaking of an organism’s body into several pieces, and some or all of which grow into adults.

What is the human life cycle? (Sexual Reproduction)

Ovary & Testis → Meiosis → Haploid Gametes & Sperm Cell → Fertilisation → Diploid Zygote → Mitosis & Development → Multicellular Diploid Adults.

What is external fertilization?

• Eggs shed by the female are fertilized by sperm outside the body of the female.

• This process commonly occurs in aquatic animals, such as fish and amphibians, where both eggs and sperm are released into the water.

What is internal fertilization?

Sperm are deposited in or near the female reproductive tract and fertilization occurs within the tract.

What is the pathway of an egg?

Ovary → oviduct → uterus → vagina → vaginal opening

What is Endometriosis?

• One of the most common gynaecological conditions

• Occurs when tissue (endometrium) lining the inside of the uterus grows outside the uterus

  • Often on organs in the pelvic and abdominal areas

• This condition is very painful for sufferers

What are the common symptoms of Endometriosis?

• Painful periods, severe cramping

• Painful intercourse

• Fatigue / Exhaustion / Low Energy

• Other Abdominal pain - Lower back pain

• Heavy / Irregular Bleeding

What causes endometriosis? how does one test for endometriosis?

• Causes - Genetics, high estrogen levels, and possibly environmental agents.

• Tests - Magnetic Resonance Imaging (MRI), ultrasound, laparoscopy

  • A laparoscopy is a form of surgery that allows viewing of the nodules or obtaining tissue for biopsy

What is the pathway of an sperm?

Testis → Epididymis → Vas deferens → Sperm duct → Urethra

What is the testis?

• The paired testes produce sperm

• The testes hang below the body, housed in the scrotum, which maintains the testes at a lowered temperature.

• Sperm are produced by meiosis in the seminiferous tubules

• Sperm are collected into the epididymis, which leads to the vas deferens.

What the accessory glands in the Male reproductive system?

• Seminal Vesicles

• Prostate Gland

• Bulbourethral gland

  • These produce the fluid portion of semen

What does the seminal vesicle do?

• Secretes a fructose-rich fluid

  • Provides nourishment for sperm

What does the prostate gland do?

• Secretes an alkaline fluid rich in prostaglandins

  • Combat acidic urethra and vagina environments and to enhance sperm motility

What does the bulbourethral gland do?

Secretes mucus for lubrication

What is Prostate cancer?

Affects 1 in 6 men in North America

• Symptoms

  • Need to urinate frequently, difficulty starting or holding back urine, painful urination

  • Difficulties with erections, painful ejaculation

  • Blood in semen and urine

  • Pain in lower back, hips and upper thighs

Risk factors for prostate cancer

• Age - Men over 55, Average age of diagnosis is 70

• Family History - Higher risk if father/brother diagnosed before age of 60

  • Among the cancers that are easiest to treat, about 89% survive at 5 years and 63% at 10 years.

What is the urinary (excretory system)

• Responsible for Excretion (gets rid of metabolic wastes)

• Among most important wastes are the nitrogenous wastes.

  • Different animals excrete nitrogenous wastes in different forms.

What is the pathway of urine?

Kidneys → ureter → urinary bladder → urethra → urinary opening

What are the two distinct regions of the mammalian kidney?

• Outer Cortex

• Inner Medulla

What is the functional part of the kidneys?

• Nephron

  • Consists of a single long tubule and a ball of capillaries called the glomerulus

What is the process the kidneys goes through?

1. Filtration

   • The excretory tubule collects a filtrate from the blood

   • Water and solutes are forced by blood pressure into the excretory tubule.

2. Reabsorption

   • Valuable substances are reclaimed from the filtrate and returned to the body fluids

3. Secretion

   • Other substances, such as toxins, are extracted from body fluids and added to the contents of the excretory tubule

4. Excretion

   • The filtrate leaves the body.

What is testicular atrophy?

• Reduction in the size of tissue responsible for sperm cells

• Symptoms

  • Decreased sex drive

  • May lead to infertility

  • Testes get shrunk

    • Due to a loss of some of the germ cells and Leydig cells

What is the causes of testicular atrophy?

• Radiation

• Chemotherapy

• Hormonal imbalance

• Steroids

• Viral infections

  • Mumps, STI’s (Gonorrhea and Syphilis)

• Old age

• Injury

What are seminiferous tubules?

Tubes inside the testes where the sperm cells are formed

What is responsible for the production of testosterone?

Leydig cells

What is an ectopic pregnancy?

• Tubal pregnancy occurs when a fertilised egg develops outside the uterus (usually in the fallopian tube)

• High risk for rupture and death.

• Annually affect less than 2% of pregnancies worldwide.

What is Mumps?

• Viral Infection of the Parotid Gland

• Becomes swollen and tender

• May spread to the other salivary glands

• Common childhood diseases before the vaccine

What is Uterine Leiomyoma?

Development of fibre nodules (also known as fibroids) in the uterus

What is Chron's disease?

• Also known as Inflammatory Bowel Syndrome (IBS)

• May involve the small and large intestine (mainly the small)

• Symptoms

  • Abdominal Pain and Diarrhoea

  • Rectal Bleeding - Bleeding may be persistent, leading to anaemia

  • Weight loss

  • Skin Problems

  • Sometimes fever

• The onset of this disease is between 15-25 years of age

• A common complication is the blockage of the intestine

  • Disease thickens the intestinal wall with swelling and scar tissue

What is sense of Sight?

• The receptors for the sense of sight are in our eyes

• Receptor: A specialised cell or tissue sensitive to a specific stimulus

What are the 3 layers of the eye? What does it contain?

• Outer / Fibrous

  • Sclera and Cornea

• Middle / Vascular

  • Choroid, Iris, Pupil

• Inner / Neuronal

  • Retina

    • Rods / Cones (Photoreceptors)

  • Optic Nerve

    • Blind Spot

What is another component of the eye, yet not part of the 3 layers?

• Lens (Focuses light by changing its shape)

  • Ciliary Body + Ligaments

  • Posterior Chamber

    • Vitreous humor (gel-like material)

  • Anterior Chamber

    • Aqueous humor (gel-like material

Rod Cells vs Cone Cells

• Rod cells do not see colour but are best for night viewing because they react to very low light levels.

• Cone cells are for colour viewing.

  • Work best in good light and are found mostly in the centre of the retina in an area called the macula lutea, which provides the sharpest vision

• Signals from rods and cones via optic nerve to the brain, which interprets the image

What is Myopia?

• When the incoming light focuses before it gets to the back of the eye (nearsightedness)

• Long eyeball, bulgy lens

• Corrected by a Concave lens

What is Hyperopia?

• When the incoming light does not focus by the time it reaches the back of the eye (farsightedness)

• Short eyeball, flat lens

• Corrected by a Convex lens

What is Cataracts?

Loss of elasticity of the lens, followed by the denaturation of crystallins, making them less transparent

What is a detached retina?

• Separation of the pigmented layer and the photoreceptor layers of the retina

• Photoreceptor cells have no access to blood vessels

• Caused by trauma to the head

What is Glaucoma?

• Elevated pressure within the eye caused by a buildup of aqueous humor

  • Eventually causes damage to the retina

  • Vision loss if not treated

What is sense of Smell?

• The receptors for the sense of smell are in our nose. They line the upper portion of our nasal cavity.

• When odorant molecules bind to specific receptors in the nasal cavity a signal is sent to the brain

What is the area in the brain that receives odour signals?

Olfactory Cortex

What is sense of Touch?

• The receptors for the sense of touch are in our skin

• We can use any part of our bodies to feel the sense of touch - some body parts are more sensitive than others

What are the three main layers of skin?

• Epidermis (Protects)

• Dermis (Receptors)

  • Detect Light and Strong Pressure

  • Also detects pain and temperature.

• Hypodermis (Protection/Insulation)

What is sense of Taste?

• The receptors for the sense of taste are located in our tongue

• The receptor cells for taste in humans are organised into taste buds.

  • Tongue receptor cells are called Gustatory cells.

What are the papillae in our tongues?

• Taste buds

  • Fungiform Papilla

  • Vallate Papilla

  • Foliate Papilla (Missing in adult humans)

• Non-taste Buds

  • Filliform Papilla (for grooming)

What are the cranial nerves associated with sense of taste?

• Facial ((VII) Anterior 2/3rd of the tongue) and Glossopharyngeal nerves ((IX) Posterior 1/3rd of the tongue)

  • Innervate the tongue, used for taste

• Vagus Nerve (X)

  • Carries taste information from the back part of the mouth

  • Used for heart rate, peristalsis, sweating, gag reflex, etc.

• Trigeminal Nerve (V)

  • Also innervates the tongue, but is used for pressure, temperature, and pain.

What is the inability to taste called? inability to smell?

Ageusia, Anosmia, respectively.

What is the sense of Hearing?

The receptors for the sense of hearing are in our ears