Excretion Flashcards
What is excretion?
Removal of metabolic waste products from the body, e.g. sweat, urea
Excretion is crucial for maintaining homeostasis.
How does excretion contribute to homeostasis?
Helps maintain body temperature, fluid balance, and removes poisonous wastes
Homeostasis is the body’s ability to maintain stable internal conditions.
What are the waste management strategies of plants?
Produce little waste, store wastes, lose more when dead structures fall off
Plants lose waste gases through stomata and lenticels.
Define ectotherms.
Animals that obtain heat from external sources
Examples include reptiles and amphibians.
Define endotherms.
Animals that generate their own body heat by internal reactions
Examples include mammals and birds.
What are the excretory functions of the lungs?
Excrete water and carbon dioxide through exhaled air
This process is part of respiratory excretion.
What is the role of the skin in excretion?
Excretes water and salts through sweat
The skin plays a vital role in thermoregulation and waste removal.
What substances are excreted by the kidneys?
Water, urea, salts, and toxins in urine
Kidneys are essential for filtering blood and maintaining fluid balance.
What is egestion?
Removal of unabsorbed waste products from the body
Unlike excretion, egestion involves solid waste.
What is the outer layer of the skin composed of?
Dead, cornified cells full of waterproof keratin
This layer provides a protective barrier against environmental damage.
What is found in the inner layer of the skin?
Living granular cells
The inner layer is responsible for growth and repair of the skin.
What is the function of sweat glands?
Produce sweat to help cool the body and excrete waste
Sweat is primarily composed of water and salts.
Fill in the blank: The _______ is involved in the removal of unabsorbed waste products.
intestines
Egestion occurs in the intestines.
What role do capillaries play in the skin?
Supply nutrients and aid in thermoregulation
Capillaries are small blood vessels that facilitate exchange.
True or False: Egestion and excretion refer to the same process.
False
Egestion involves solid waste, while excretion involves metabolic waste.
What is the granular layer at the base of the skin called?
Malpighian layer
The Malpighian layer is responsible for making new cells and contains many melanin cells.
What strong protein is found in the dermis?
Collagen
Collagen provides strength and structure to the skin.
What components are found in the dermis?
- Blood vessels
- Sweat glands
- Hairs
- Sebaceous glands
- Nerve receptors
These components contribute to the skin’s functions and sensation.
What tissue is found in the subcutaneous layer?
Adipose tissue
Adipose tissue contains fat, which serves as an energy store.
What is one function of the epidermis?
Protection
The epidermis protects against damage, water loss, and pathogen entry.
How does melanin protect the skin?
Against UV radiation
Melanin absorbs harmful UV rays from the sun.
What does sebum do for the epidermis?
Keeps it intact
Sebum is an oily substance that helps to maintain skin hydration.
What vitamin is produced in the skin?
Vitamin D
Vitamin D is essential for various bodily functions, including calcium absorption.
What is the skin’s role as a sense organ?
Organ of touch
The skin contains sensory receptors that detect touch, pressure, and temperature.
What does sweat remove from the body?
Water and salts
Sweating is a crucial process for maintaining fluid balance and temperature regulation.
What happens to blood vessels in cold conditions?
Constrict (vasoconstriction)
This process helps retain heat in the body.
What is the effect of warm conditions on the body?
- Sweating
- Vasodilation
Sweating cools the body through evaporation, while vasodilation helps lose heat.
What are the main components of the urinary system?
- Two kidneys
- Two ureters
- Bladder
- Urethra
These components work together to manage waste and fluid balance in the body.
What is one function of the kidneys?
Excretion of water, salts, and urea
This function is vital for maintaining homeostasis in the body.
What is osmoregulation?
The process of maintaining water and salt balance in the body
It is a key function of the kidneys to ensure proper hydration and electrolyte levels.
What is the primary role of the nephron?
Carries out the functions of the kidneys
Nephrons are the functional units of the kidneys, essential for urine formation.
Where are nephrons located within the kidney?
In the cortex and medulla of the kidney
The cortex is the outer region, while the medulla is the inner region of the kidney.
What is the first step in urine formation by the nephron?
Filtration
This process begins when blood enters the nephron at the afferent arteriole.
What structure within the nephron is responsible for filtration?
Glomerulus
The glomerulus is a network of capillaries that filters blood under high pressure.
What happens to red blood cells and proteins during filtration in the glomerulus?
They do not enter the glomerular filtrate
Red blood cells and larger molecules like proteins are too large to pass through the filtration barrier.
What does glomerular filtrate consist of?
A dilute solution of waste and useful molecules
The filtrate includes substances that can be either reabsorbed or excreted.
What is the second step in the urine formation process?
Reabsorption
This step involves reclaiming water and useful molecules from the filtrate.
Which part of the nephron reabsorbs water by osmosis?
Proximal tubule
The proximal tubule is crucial for reabsorbing water and salts.
How are salts reabsorbed in the proximal tubule?
By diffusion and active transport
This ensures essential electrolytes are retained in the body.
What is the role of the loop of Henle in reabsorption?
Reabsorbs water by osmosis in the descending loop and salts by diffusion
The loop of Henle plays a key role in concentrating urine.
What occurs in the distal tubule regarding reabsorption?
Absorbs water by osmosis and some salts by active transport
This final step of reabsorption helps regulate body fluid balance.
Fill in the blank: Blood enters the nephron at the _______.
afferent arteriole
The afferent arteriole brings blood to the nephron for filtration.
What do the collecting ducts absorb?
Water by osmosis
Where is ADH produced?
Hypothalamus
Where is ADH released into?
The blood from the pituitary gland
What does ADH control?
The volume of urine formed
What substances can be secreted into the nephron?
Hormones and ions
Which ions are secreted in the distal convoluted tubule for pH control?
Potassium and hydrogen ions
What is the pathway of urine after it leaves the collecting ducts?
To the ureters and then to the bladder
What stimulates the production of ADH?
Lack of water in the plasma
What effect does ADH have on the distal tubule and collecting ducts?
Increases reabsorption of water
Fill in the blank: Water is returned to the plasma and less urine is _______.
Released
List the key components of the kidney anatomy mentioned.
- Cortex
- Medulla
- Renal artery
- Renal vein
- Pelvis
