Human Bio exam #1.

Urinary system

Organs responsible for producing, storing, and eliminating urine.

kidneys

Primary excretory organ

2 reddish-brown "bean - shaped" organs.

renal capsule

Membranous sheath that covers kidneys

cortex

outer layer of kidney

medulla

inner layer of kidneys, the renal pyramids collectively

renal pyramids

consists of tubules that transport urine from cortex to calyx

renal pelvis

carrise urine to bladder, via the ureter.

nephron

Microscopic structure responsible for filtering blood, removing waste products, and regulating water, salts and pH balance.

Nephron - location

spans the renal cortex and medulla

Nephron - function

site of ion and water reabsorption, and where urine is produced.

Nephron surface area

Each kidney has over a million nephrons

Each neprhon has two convolutions (proximal and distal) and a large loop (loop of henle)

Renal corpuscle

Glomerular capsule and glomerulus combined.

Glomerular/bowman’s capsule

Surrounds the glomerulus to collect the fluid filtered out of the blood. Site of filtration.

Glomerulus

A cluster of capillaries located within the glomerular capsule. Site of filtration.

Afferent arteriole

Transports blood to the glomerulus in the kidney. Has a larger lumen, which helps in increasing blood flow into the glomerulus for filtration. Blood from afferent arteriole is received by the renal artery from the aorta.

efferent arteriole

Transports blood away from the glomerulus after filtration. It carries blood through the capillaries that surround the nephron tubules, where nutrients, water, vitamins, and minerals are reabsorbed.

renal tubule

• Proximal convolute tubule (selective reabsorption and tubular secretion)

• Loop of henle (selective reabsorption)

• Distal convoluted tubule (selective reabsorption and tubular secretion)

proximal convoluted tubule

First segment of the renal tubule after the glomerulues, where most reabsorption of water, ions and nutrients occurs.

descending limb (loop of henle)

Part of the nephron loop that extends into the medulla; it allows water to be reabsorbed, concentrating the filtrate.

loop of henle

A U-shaped segment of the nephron that reates a concentration gradient in the kidney, essential for water reabsorption and urine concentration. 

ascending limb (loop of henle)

The segment of the nephron loop that moves into the medulla; it is impermeable to water but allows salts to be reabsorbed, diluting the filtrate.

distal convoluted tubule

The later segment of the nephron tubule where further reabsorption and secretion occur, helping to regulate blood pH, ion balance, and blood pressure.

collecting duct

The duct that collects urine from multiple nephrons and channels it toward the renal pelvis.

renal artery

The blood vessel that supplies oxygenated blood from the aorta to the kidneys for filtration.

renal vein

the blood vessel that carries filtered, deoxygenated blood away from the kidneys back to the inferior vena cava.

peritubular capillary

a network of tiny blood vessels that surrounds the renal tubules, allowing for the exchange of substances during reabsorption and secretion.

renal artery (blood suppy)

brings blood to kidney

afferent arteriole (blood supply)

enters renal corpuscle

glomerulus (blood supply)

a knot of capillaries within the renal corpuscle

efferent arteriole (blood supply)

exits the renal corpuscle

Peritubular capillaries (blood supply)

capillary network surrounding renal tubule

renal vein (blood supply)

moves blood away from kidney.

excretion

removal of wastes of metabolism from the body

metabolism

term used to describe all chemical reactions involved in maintaining the living state of all cells and organisms. Every cell produces waste products.

excretory organs

organs involved in the proessing of wastes of in the excretion of those wastes.

excretory organ: lungs

waste products: carbon dioxide and water

source of waste product: cellular respiration

excretory organ: sweat glands

organ removing waste: skin (sweat glands)

waste products: water, NaCl, urea, lactic acid

excretory organ: alimentary canal

organ removing waste: intestines

waste products: bile pigments

excretory organ: kidney

role: principle excretory organ

waste products: nitrogenous compounds

excretory organ: liver

waste products: processing many substances so that they can be excreted (urea, carbs and water)

urinary organs

kidneys

bladder (holds urine)

ureter (ducts which joins the kidneys and bladder)

urethra (tube which urene is excreted from and semen in males)

liver

located in the upper abdominal cavity

very large organ with many different functions.

all the blood leaving the stomach and intestines passes through the _____.

functions of the liver

• breaks down excess protein

• preparations of materials for excretion - conversion of harmful ammonia to urea

• production of bile, which helps carry away waste and break down fats in the small intestine during digestion.

• breaks down toxic substances and most medicines - an excess of toxins, one of which is alcohol, may cause permanent damage to the liver.

• breaks down hemoglobin from dead red blood cells, creating products that are added to bile and then disposed of through the digestive system.

When the liver has broken down hamrful substances, they are excreted into the bile or blood:

• bile by-products enter the intestine and utlimately leave the body in the faeces.

• blood by-products are filtered out by the kidneys and leave the body in the form of urine.

deamination

removal of amino group from an amino acid.

• nitrogen occurs in the amino (NH2) part of an amino acid

• NItrogen is toxic to the human body and must be removed.

After deamination

The NH2 is converted into ammonia (NH3) and then to urea.

the cells of the liver rapidly convert ammonia to the less toxic molecule urea.

ammonia

extremely solube in water and highly toxic to cells.

urea

harmless in moderate amounts and easily excreted. small amounts is also lost through sweat.

after conversion of ammonia to urea

remaining part of the amino acid is made up of mostly carbon and hydrogen and is converted into carbohydrates that can be used as a source of energy.

functions of kidney: water

ensures that there’s not too much or too little water in the body

functions of the kidney: balance

maintains balance of electrolytes, critical for heart rhythm

functions of the kidney: bones

activates vitamin D, which helps the body absorb calcium

functions of the kidney: blood pressure

makes sure that pressure isn’t too high or too low

functions of the kidney: wastes

gets rid of urea, uric acid, toxins, and other wastes via urine.

functions of the kidney : blood

releases erythroprotein, which tells bone marrow to make red blood cells.

Levels of organisation

The hierarchy of biological structure in the human body

Cell

Basic structural and functional unit of all living things

Tissue

A group of similar cells working together to perform a specific function

Organ

A group of different tissues working together to perform a specific function

System

A group of organs working together to perform a specific function

Types of tissues

Four main categories of tissues in the human body

Epithelial tissue

Tightly packed sheets of cells that cover surfaces and line body cavities; forms membranes and skin

Examples of epithelial tissue

Alveoli of lungs and outer layer of skin

Connective tissue

Tissue with cells widely spaced in a matrix that supports, binds and joins other tissues

Examples of connective tissue

Bone, cartilage, ligaments, tendons, adipose tissue and blood

Muscular tissue

Tissue that contracts and relaxes to produce movement

Skeletal muscle

Striated muscle attached to bones; voluntary control

Smooth muscle

Non

Cardiac muscle

Striated, branched muscle found in the heart; involuntary control

Nervous tissue

Tissue that transmits nerve impulses throughout the body

Neurons

Nerve cells with long cytoplasmic extensions that transmit electrical signals

Cell organelles

Structures within cells that carry out specific functions

Cell membrane

Controls movement of substances into and out of the cell

Cytoplasm

Jelly

Ribosomes

Site of protein synthesis

Nucleus

Controls cell activities and contains genetic material

Mitochondria

Site of aerobic respiration and ATP production

Lysosome

Contains digestive enzymes to break down waste materials

Golgi apparatus

Modifies and packages proteins for secretion

Endoplasmic reticulum

Network involved in chemical reactions and transport within the cell

Rough endoplasmic reticulum

Endoplasmic reticulum with ribosomes attached; protein synthesis

Smooth endoplasmic reticulum

Endoplasmic reticulum without ribosomes; lipid synthesis and detoxification

Centrioles

Involved in spindle fibre formation during cell division

Cell membrane permeability

Cell membrane is selectively permeable, allowing some substances to pass and others not

Fluid mosaic model

Describes the cell membrane as a phospholipid bilayer with embedded proteins in constant motion

Phospholipid molecule

Has a hydrophilic head and hydrophobic tail

Passive transport

Movement of substances down a concentration gradient without energy

Simple diffusion

Movement of small, fat

Facilitated diffusion

Movement of substances through the membrane using carrier or channel proteins

Osmosis

Diffusion of water across a semi

Active transport

Movement of substances against a concentration gradient using energy (ATP)

Vesicular transport

Movement of materials using membrane

Endocytosis

Transport of substances into the cell using vesicles

Exocytosis

Transport of substances out of the cell using vesicles

Phagocytosis

Uptake of solid material into the cell

Pinocytosis

Uptake of liquid material into the cell

Surface area to volume ratio

Ratio affecting how efficiently materials are exchanged in cells

Effect of high surface area to volume ratio

Increases the rate of exchange of materials

Concentration gradient

Difference in concentration between two areas

Effect of concentration gradient on diffusion

Greater difference increases diffusion rate