Homeostasis (Excretory system) Flashcards
List the structures in the excretory pathway, from where filtrate enters the nephron to the excretion of urine form the body
Bowmans’s space > proximal convoluted tubule > descending limb of the loop of henle > ascending limb of the loop of henle > distal convoluted tubule > collecting duct > renal pelvis > ureter > bladder > urethra
List the vessels in the renal vascular pathway, starting from the renal artery and ending at the renal vein
Renal artery > afferent arteriole > glomerulus > efferent arteriole > vasa reacta > renal vein
What arm of the nervous system is responsible for contraction of the detrusor muscle?
The parasympatheic nervous system causes contraction of the detrusor muscle
What are the three processes by which solutes are exchanges between the filtrate and the blood? What happens in each?
- Filtration- it is the movement of solutes from blood into filtrate at Bowman’s capsule
- Secretion- It is the movement of solutes from blood into filtrate anywhere besides Bowman’s capsule
- Reabsorption- it is the movement of solutes from filtrate into blood
Bowman’s capsule
Site of filtration, through which water, ions, amino acids, vitamins, and glucose pass ( everything except cells and proteins)
Proximal convoluted tube
Controls solute identity, reabsorbing vitamins, amino acids and glucose, while secreting potassium and hydrogen ions, ammonia and urea
Descending limb of the loop of henle
It is important for water reabsorption using the medullary concentration gradient. Permeable to water, so water reabsorbed
Ascending limb of the loop of henle
Permeable to solutes so solutes reabsorbed and not permeable to water. Important for salt reabsorption and allowing dilution of urine in the diluting segment
distal convoluted tube
Important for solute identity by reabsorbing salts while secreting potassium and hydrogen ions, ammonia, and urea
Collecting duct
It is important for urine concentration; its variability permeability allows water to be reabsorbed based on the needs of the body
How does the kidney control the acid-base balance?
When the blood pH is low, the kidneys excrete H+ ions and increase absorption of bicarbonate, resulting in vice versa.
What happens when blood osmolarity is low?
Excess water will be excreted, while solutes will be reabsorbed in higher concentrations and vice versa.
Distal convoluted tube responds to what hormone?
Aldosterone (steroid hormone)
Collecting duct responds to what hormone?
Aldosterone (steroid hormone) and antidiuretic hormone (ADH or Vasopressin- peptide hormone) . It reabsorbs water by increasing the permeability of collecting duct but h20
Difference between Aldosterone and antidiuretic hormone?
ADH governs water reabsorption and thus results in a lower blood osmolarity (greater h20 in blood).It reabsorbs na from convoluted tubule and collecting duct. Aldosterone causes both salt and water reabsorption and does not change blood osmolarity
What is the predominant cell type in the epidermis?
Keratinocytes are the primary cells of the epidermis
What are the layers of epidermis, from superficial to deep?
Stratum corneum, Stratum lucidum, Stratum granulosum, Stratum spinosum, Stratum basal
What are the layers of the dermis, from superficial to deep?
The papillary layer and reticular layer
What are the cooling mechanism used by the body?
Cooling mechanism include sweating, which absorbs heat from the body through evaporation of water from sweat, and vasodilation. Sweat glands are innervated by postganglionic cholinergic sympathetic neurons
What is the warming mechanism used by the body?
Warming mechanism include piloerection, in which arrector pili muscles contract, causing hair to stand on end ( trapping a layer of warmed air around the skin), vasoconstriction, shivering and insulation provided by fat.
Where are most sensory cells located? And what are some examples?
In the dermis
- Merkel cells (deep pressure and texture)
- free nerve ending (pain)
- Meissner’s corpuscles (light touch)
- Ruffini endings (stretch )
Pacinian corpuscles (deep pressure and vibration)
Hypodermis
Deepest layer of the skin
- Contains fat and connective tissue and connects the skin to the rest of the body
Langerhans cells
Special macrophages that serve as antigen-presenting cells in skin
- in stratum spinosum
How is Na+ transported?
Na+ is actively transported out of the nephron in the proximal and distal convoluted tube where concentration outside is greater than inside, this energy is need to move Na+ against its gradient. But in the ascending tube, Na+ is moved passively down the gradient.
What regulates body temp?
hypothalamus
- When its cold outside, nervous stimulation to the blood vessels in the skin is increased, causing vessels to constrict. This constriction diminishes blood flow to the skin surface and prevents heat loss. Sweat glands are turned off to prevent heat loss through evaporation. Skeletal muscles are stimulated to shiver (rapidly contract), which increases the metabolic rate and produces heat.
What layer of skin is mostly loose connective tissue?
Papillary layer of the dermis
Which layer of the epidermis contain dead keratinocytes?
Stratum corneum and stratum lucidum
What does reticular layer contain in dermis?
Dense connective tissue
