MCAT Biology - Homeostasis

Chapter 10 - Excretory and Integumentary system

Cortex

Outermost layer of kidney

Medulla

Sits within cortex

Renal Hilum

deep slit in center of its medial surface

Portal system

two capillary beds in series through which blood must travel before returning to the heart

Transitional epithilium

contain cells that change shape in response to bladder elascity

Detrusor muscle

muscular linging of the bladder

Filtration

movement soluts from blood to filtrate at Bowsman’s capsule

secretion

movement of solutes from blood to filtrate anywhere besides Bowman’s capusle

Reabsorption

movement of solutes from filtrate to blood

Proximal Convuluted Tube

amino acids glucose water souble vitamins majority salts reabsorbed along water

Interstitium

connective tissue surrounding the nephron

Countercurrent multiplier system

the flow of filtrate through loop of henle is in the opposite direction of the flow fo blood through vasca recta

Aldosterone

steriod hormone secreted by adrenal cortex in response to decreased blood pressure

Angiotensin II

promotes release of aldosterone from the adrenal cortex

Osmotic pressure

Sucking pressure that draws water into the vasculature caused by all dissolved particles

Oncotic pressure

osmotic pressure that is attributable to dissolved proteins specifically

Strata

layers of epidermis

Layers of epidermis

Stratum basale > Stratum spinosum > Stratum granulosome > Stratum lucidum > Stratum corneum

Stratum Basale

contain stem cells and is responsible for proliferation of keratinocytes

Stratum Spinosum

cells become connected to eachother site of Langerhan cells

Stratum granulosome

keratinocytes die and lose their nuclei

Stratum lucidum

present in thick, hairless skin

Stratum corneum

cotain several dozen layer of flattened keratinocytes, forming a barrier prevents invasion by pathogen that helps to prevent loss fo fluid and salts

Keratinocytes

predominant cells of skin produce keratin

Calluses

form from excessive keratin deposition in areas of repeated strain due to friction

Melanocytes

cell type derived from neural crest cells and found in stratum basale and produce melanin

melanin

pigment serves to protect skin from DNA damaged caused by UV radiation

Langerhan cells

reside in stratum spinosum, capable presenting antigen to T cells to activate immune system

Papillary layer

upper layer of dermis consists of loose connective tissue

Recticular layer

Below papillary sweat gland blood vessle hair follicles

Merkel cell

responsible deep pressure and texture sensation within the skin

Meissner corpuscle

respond to light touch

Ruffini ending

respond to stretch

Pacinian corpuscles

respond deep pressure and vibration

Hypodermis

layer connective tissue connects to epithelium to rest of body

pilorection

hairs of skin stand up on end , helps trap layer heated air near skin

white fat

layer of fat below skin helps to insulate the body