Unit 4 Flashcards
(29 cards)
What type of tissue is adipose tissue?
Specialized connective tissue composed mainly of adipocytes.
List 5 functions of adipose tissue.
Energy storage, thermal insulation, body shaping, protection, endocrine (leptin secretion).
What is leptin and its function?
A hormone from WAT
function:
1. Appetite Suppression (Satiety Signal):
Leptin travels through the bloodstream to the hypothalamus in the brain.
There, it reduces the sensation of hunger and increases energy expenditure.
It signals to the brain that the body has enough fat stored and does not need more food.
- Energy Homeostasis:
Helps maintain a balance between energy intake (eating) and energy expenditure (metabolism and activity).
High leptin levels = full/satiated
Low leptin levels (e.g. fasting) = increased appetite and reduced metabolism
How is white adipose tissue structured?
Unilocular (one large fat droplet), well vascularized, with peripheral nuclei.
What are the main locations of white adipose tissue?
Subcutaneous fat, yellow bone marrow, visceral fat.
What is the function of brown adipose tissue (BAT)?
Thermogenesis — production of heat via UCP1 in mitochondria.
Why is BAT brown?
Due to high mitochondrial content and rich vascularization.
What is ‘browning’ of white adipose tissue?
Conversion of WAT into ‘brite’ cells with BAT-like function, induced by cold, exercise, or certain foods.
What causes hypertrophic vs. hyperplastic obesity?
Hypertrophic: enlarged adipocytes (adults).
Hyperplastic: increased number of adipocytes (childhood origin).
What structural changes occur in adipose tissue with obesity?
Inflammation, M1 macrophage infiltration, cytokine release, ECM stiffness.
What are the two main components of blood and their percentages?
Plasma (55%) and formed elements (45%).
What’s the difference between plasma and serum?
Plasma has fibrinogen; serum does not (serum = plasma – fibrinogen).
What are the formed elements in blood?
Red blood cells (RBCs), white blood cells (WBCs), and platelets.
What are the features of RBCs?
Anucleated, biconcave, flexible, filled with hemoglobin, 120-day lifespan.
What is hematocrit?
The percentage of blood volume made up of RBCs.
How are platelets formed?
From fragmentation of megakaryocytes; involved in clotting.
Name and function of three granulocytes.
Neutrophils: Phagocytosis of bacteria. Eosinophils: Combat parasites and allergies. Basophils: Release histamine; mediate inflammation.
What are agranulocytes and their roles?
Lymphocytes: B and T cells (adaptive immunity), NK cells (kill infected cells). Monocytes: Become macrophages in tissue; phagocytic.
Where does hematopoiesis occur in adults?
Red bone marrow of flat bones, vertebrae, pelvis, and epiphyses of long bones.
What are the general characteristics of cartilage?
Avascular, flexible, strong ECM, contains chondrocytes in lacunae.
What are the three types of cartilage?
Hyaline, elastic, fibrocartilage.
What is the function and location of hyaline cartilage?
Smooth joint surfaces, support; found in joints, trachea, nose, ribs.
What distinguishes elastic cartilage?
Contains elastic fibers; found in the ear, epiglottis.
What distinguishes fibrocartilage?
Dense collagen, very strong, no perichondrium; found in intervertebral discs, menisci.
